Social software

share bookmarks

 * del.icio.us
 * very useful because of accessing your bookmarks from everywhere
 * tags for every bookmark are helpful to find and organize them
 * see someone's bookmarks (if you know his nick) by entering http://del.icio.us/nickname
 * Wikipedia about del.icious
 * del.ico.us-extension for Firefox
 * extispicious gives you a textual scattering of a user's tags, sized according to the number of times that they've used each of them
 * del.irio.us
 * similar to del.icio.us, but open source
 * content is licensed under a Creative Commons license

share photos

 * flickr
 * you can upload photos and pics and tag it
 * recently purchased by yahoo


 * commons.wikimedia
 * upload pictures and choose your own license (go public domain or "dual-license")

share movies
put your clips online
 * [YouTube]
 * [FilePut]

music
last.fm

meme trading
not really software but still very social
 * BookCrossing
 * FlashMob

Geographical
Software around the world
 * Foundcity
 * Foundcity is a social mapping tool for creating a personalized map of your life on-the-fly. From your computer or cell phone, you tag locations, add photos, label them with any words you want, and plot them to your map, which you can share with friends, keep private, or publish openly.
 * plazes
 * Plazes is a grassroot approach to location-aware interaction, using the local network you are connected to as location reference. It allows you to share your location with the people you know and to discover people and plazes around you.

networking
not really web services, more remains of the community hype
 * orkut
 * powerd by google
 * openbc
 * business network