SHOPPING & LIFESTYLE zunafish.com
Sign up here to trade DVD's, CD's, paberbacks, video games and more. The only money that changes hands is the $1 fee you pay the site for each successful trade. It's easy to post an item: you simply plug in identifying information--the site walks you through that--and the Web elves produce a full listing. The sole limitation--apart from those of your collection--is that you can only swap like items (CDs for CDs, books for books etc.). So choose a screen name, and start swapping.
STAYING CONNECTED dodgeball.com
Let your mobile device improve your social life. Use this service to corral friends for a drink or find out where they're already hanging. All you do is send a text message to the mother ship, and it does the rest: the service locates you, checks which of your buds are nearby and sends out the appropriate alerts. And the Dodgeball team keeps growing: it's now at play in 22 cities.
WEB SEARCH & SERVICES pixsy.com
This clever search engine extracts images and videos from the news feeds of a variety of content providers, from YouTube to the BBC. Click on a source--say, the New York Times--from the "Browse Recently Added" box on the home page, and you will get a fresh batch of thumbnails, which serve as direct links to the news material. Or you can browse by category. Currently stocking some 10 million items in its searchable index, Pixsy intends to have 1 billion items by the end of the year.
TIME WASTERS number-logic.com
Caught up in the current sudoku craze? This site offers a hefty supply of puzzles. Work independently, or compete head to head against other registered users. There are four levels of difficulty. The site will time you (although there is a PAUSE button) and, if you wish, "validate" your answers (and highlight any mistakes). You don't have to sign in to use the site--unless you want your scores recorded.
NEWS & INFORMATION digg.com
At this so-called social news users, rather than a computer algorithm, determine how important or interesting the stories are, and Digg posts them on its home page accordingly. The articles are tagged with the number of "diggs," or positive votes, from readers. Click on "Switch to Cloud View" in "Upcoming Stories" to see which stories are gaining traction (the headlines appear bigger). And don't miss the new Digg Labs page, offering two visual alternatives to displaying the same info: Swarm http://labs.digg.com/swarm) which looks like a cluster map, and Stack http://labs.digg.com/stack) which resembles more of an expanding and contracting bar graph. Watch the hype as it actually happens.
ARTS & MEDIA pandora.com
Type in the name of your favorite band, and within moments the site will be streaming a radio station, featuring songs from that band and similar ones, to your desktop through your browser--no registration and no downloads required. You can fine-tune the playlist by using the thumbs-up and thumbs-down buttons. It's a nifty way of discovering new artists who sort of sound like the bands you already like, and of becoming a font of music knowledge at parties. A new Backstage section is a searchable directory of artists and albums--"your door to the music universe"--courtesy of the Music Genome Project.
TRAVEL & REAL ESTATE yelp.com
Read what paying customers--not critics--are saying about restaurants, hotels, nightclubs and so on, in New York City; Seattle; Phoenix, Ariz.; and 21 other cities, or submit written reviews of your own. The site combines strong local search tools (like Google Maps) with a social networking approach--already the site is teeming with "Yelpers" eager to share--and the more user-generated content it compiles, the more useful it will be. So go out, eat and yelp. It's your civic duty.
For the full annual list of TIME's 50 coolest websites, including shopping, cooking and parenting blogs, please visit time.com/coolest