The online world has changed dramatically even since we last drew up a list of 100 useful sites in December 2006. In the interim, there has been a revival of the browser wars - with Google's Chrome and Apple's Safari making surprising inroads into the Windows monopoly, and offering a new vision of what browsing can be like.
Many of the sites listed here were not available when we did our last list; although longevity is a mark of pride online, it is difficult for companies set up in the 1990s to reinvent themselves quickly enough to take advantage of new technologies. Although of course rapid change brings casualties too: it's possible that with all the economic turbulence going on that some of the sites here won't be around in a year from now, or that their now free services will have become paid-for. That doesn't diminish their usefulness, though; it just underlines their determination to survive.
The biggest changes since 2006 have been in the fields of collaborative online services that let people in different locations work simultaneously on projects. Collaboration in 2006 was very much focused on words, but now you can create presentations that look as though they were made with expensive packages. And then you can share those presentations, or look at other work that people have done - and even download them. You can convert files without needing expensive systems. Collaborative working has never been easier, even across different platorms. The web really is becoming the operating system, as the rise of the "netbooks" (aka ultraportables, aka Liliputers) emphasises.
The growth of location-based services - particularly those which you can choose to log yourself in and out of, thus protecting your privacy - has been rapid. A parallel growth has come with the mobile web; there's no escaping the fact that Apple's iPhone has revolutionised how its users, in their millions, think about the internet. For them, it is no longer something that is experienced well on a computer and then badly on their mobile phone; the mobile version of Safari has made browsing on the move an altogether more pleasant experience, which it never was before.
That opens up new vistas: location-aware task managers can adjust the order of your to-do list based on what the GPS unit in the phone is telling you, so that while you're in the supermarket it will remind you about the cereal you need, but in the office it will tell you to send that important memo right away.
Video, of course, is now everywhere. YouTube was already dominant in 2006, but now the BBC's iPlayer is taking over. If it makes its technology available to all, perhaps the UK will become a nation of video makers and watchers.
So here are our 100 revised best sites to see you through the next couple of years. They're organised roughly along those lines.
BloggingNow as easy as falling off a log.
http://www.guardian.co.uk/technology/2008/dec/18/internet-websites
Bloglines bloglines.com for reading web feeds. Smart and clean.
Wordpress wordpress.com free, and most importantly spam-free, blogging.
BrowsersA newly revived category, thanks to Chrome and Safari.
Chrome google.com/chrome newly out of beta, though Windows-only.
Firefox mozilla.com/firefox infinitely malleable, with fewer security holes.
Flock flock.com with an emphasis on linking to social networks.
Opera opera.com growing in importance for mobiles.
Safari apple.com/safari Apple's contender; a leader in mobile web access.
CartoonsEveryone needs some relaxation.
Dilbert dilbert.com hi, cube-dwellers.
Alex alexcartoon.com amid the financial crisis, Alex the banker remains reliably self-interested.
Doonesbury doonesbury.com the cartoon you'll also find in that printed newspaper thing.
The Joy of Tech geekculture.com/joyoftech well-drawn, witty near-daily takes on Apple and computing life.
XKCD xkcd.com "Stick-figure strip featuring humour about technology, science, mathematics and relationships."
Create/collaborate The main change from last time: whatever you want to do, wherever you are.
Dipity dipity.com build timelines and add text, pictures and videos.
Zoho zoho.com everything in one place, from documents to presentations.
Rememberthemilk rememberthemilk.com online task/to-do management.
Netvibes netvibes.com your to-do lists, news, weather and photos on one page.
280slides 280slides.com create presentations online. Very slick.
Zamzar zamzar.com convert files from one format to another.
GamingA field where handheld, bedroom and Flash games are becoming mainstream
Eurogamer eurogamer.net reportage, with breadth, if not always depth.
The Independent GamingSource tigsource.com a great place to pick up on tomorrow's breakthrough hits.
Pocket Gamer pocketgamer.co.uk still by far the best site on handheld gaming.
Metacritic metacritic.com/games industry touchstone and useful one-stop buying guide.
Jay is Games jayisgames.com passionate, well-designed and knowledgeable.
Geek squadStack Overflow stackoverflow.com where programmers gather.
The Daily WTF thedailywtf.com daily despatches from the coding warzone.
Joel On Software joelonsoftware.com essays by a former Microsoftie.
Government/public services/politicsStreetwire streetwire.org hyperlocal information including planning alerts, crime and public safety, traffic, local news and postings to FixMyStreet.com.
Recycle Now recyclenow.com winner of the Show Us A Better Way competition.
British and Irish Legal Information Institute bailii.org a database of laws. Only survives hand-to-mouth on voluntary donations; where's yours?
What Do They Know? whatdotheyknow.com makes filing a Freedom Of Information request as easy as sending an email. Too easy, some in power think.
Upmystreet upmystreet.com all the detail on your area you could ever want.
Location, locationServices like these blossom with a mobile phone that can access the internet
Dopplr dopplr.com "share your future travel plans with friends and colleagues", then find out if others will be there too.
Qype qype.com localised search for pubs, restaurants, etc; also a bit of a social network.
Loopt loopt.com "transforms your mobile phone into a social compass".
Brightkite brightkite.com a "location-based social network".
Maps The flip side of location-based services: seeing where you are.
OpenStreetMap openstreetmap.org a rights-free map created by people like you. Remarkably detailed and precise.
Walkit walkit.com walking directions for all sorts of routes.
Google Maps Street View maps.google.com/help/maps/streetview soon to have the UK as well.
Noise pollution map noisemapping.defra.gov.uk how noisy is it in the area around your house?
Where's The Path? wheresthepath.googlepages.com/wheresthepath.htm Let down by OS's absurd OpenSpace restrictions.
Money/finance/ consumer fightbackWe all need someone on our side.
Money Saving Expert moneysavingexpert.com does what it says on the tin.
BView bview.co.uk review businesses before you use them.
Say No to 0870 saynoto0870.com direct-dial numbers, not expensive national-rate ones.
Consumer Direct consumerdirect.gov.uk government site for consumers.
Zopa zopa.com a human-centred way to loan money to people in the developing world.
MusicLast.fm last.fm British-made, CBS-owned, music recommendation station.
Amazon amazon.co.uk now has its own MP3 store in the UK as well as the US.
7Digital 7digital.com music downloads in MP3 format - so not tied to iPods.
Passionato passionato.com classical music MP3 downloads, slowly building momentum.
Songkick songkick.com find out where your favourite bands are playing next, based on your music library.
Blip.fm blip.fm be your own DJ and create a social network from your choices and recommendations.
News recommendationDigg digg.com still the reigning champion.
Reddit reddit.com slightly upmarket from Digg; slightly below...
Techmeme techmeme.com technology news chosen by computer, though it's now adding human editors.
Popurls popurls.com aggregating the aggregators: the web in a window.
Slashdot slashdot.org still attracts a big, and often knowledgable, audience.
OffbeatThe Onion theonion.com still the satirical newspaper of record.
B3TA b3ta.com beyond classification; its forum has spawned many memes... and trolls.
Lolcats icanhazcheezburger.com captioned cats and other animals.
PostSecret postsecret.blogspot.com notes of secrets sent by people who want them posted. So they are.
Passive-Aggressive Notes passiveaggressivenotes.com would it be too much trouble for you to have a look?
PhotographyFlickr flickr.com the granddaddy of photo-sharing sites.
Picnik picnik.com photo editing in your browser.
Picasa picasa.com Google's photo organisation and editing tool.
• This article was amended on 3 June 2009. The original said that Picasa was Windows only. That is no longer the case.
Physical from virtual Moo moo.com Moo business cards have become a calling card in themselves.
Blurb blurb.com coffee-table book publishing of your books.
Lulu lulu.com book, photobook, calendars and other sorts of publishing.
Cafepress cafepress.com badges, T-shirts etc. US-only at present.
Spreadshirt spreadshirt.net design your own T-shirt or sweatshirt and get it printed.
ReferenceCIA Factbook cia.gov/library/publications/the-world-factbook all the data you need on pretty much anywhere.
Wikipedia wikipedia.com still a first port of call on most topics.
Rotten Tomatoes rottentomatoes.com check the film you plan to see here.
Internet Archive/Wayback Machine archive.org the web in aspic.
Wikileaks wikileaks.org anonymous source of leaked documents.
SearchGoogle still dominates.
Clusty clusty.com results in clouds.
CoolIris cooliris.com image-based searching - a new way to use the web.
Social softwareChances are high you're a member of at least one, and perhaps all, of these sites.
Facebook facebook.com virtually everyone's your friend here.
Myspace myspace.com hangout for all the teenagers. And Kirk Douglas.
LinkedIn linkedin.com mainly for business.
Friends Reunited friendsreunited.co.uk the original social network.
Twitter, and associatedTwitter has proved itself over and over this year as a vector for news.
Twitter twitter.com the ur-site, where you can create an identity (or several).
Monitter monitter.com watch keywords on Twitter. A brand, your name, a meme? No login required at present.
Matt themattinator.com post to multiple Twitter accounts. Requires your password; only give if you trust the site.
Twitterfeed twitterfeed.com posts blog contents to Twitter. Requires password; only give if you're sure that you trust the site. We do.
Twitter Grader twitter.grader.com find how you rank on Twitter.
VideoBBC iPlayer bbc.co.uk/iplayer already taking up 10% of UK network traffic.
YouTube youtube.com dominant provider of video content online.
Vimeo vimeo.com better rights control than YouTube and a cleaner interface.
Worldtv.com worldtv.com set up your own global TV channel.
Qik qik.com video-sharing from your mobile.
Joost joost.com internet TV via a browser plugin.
Videojug videojug.com a sort of social network of informational video.
Seesmic seesmic.com short video conversation: another social network.
Virtual worlds/MMORPGsRunescape runescape.com amazingly successful MMORPG.
Entropia Universe entropiauniverse.com set in a distant future on the untamed planet of Calypso.
Club Penguin clubpenguin.com minigame-tastic virtual world for kids.
Moshi Monsters moshimonsters.com "educational" virtual world for kids.
VisualisationDabbleDB dabbledb.com create online databases and analyse them.
Google Visualisation tools code.google.com/apis/visualization/documentation/gallery.html dozens of tools for making data more comprehensible.
Many Eyes manyeyes.alphaworks.ibm.com/manyeyes/page/Visualization_Options.html IBM's visualisation tools, similar to Google's.
• Which essential sites have we missed? Tell us on the Technology blog
· This article was amended on Friday December 19 2008. We originally gave the wrong address for the local information website Streetwire. It is streetwire.org. This has been corrected
