Social Bookmarking Sites for All Occasions

Getting onto the front page of these social bookmarking sites may not deliver the server crashing traffic of Digg, Reddit, or StumbleUpon, but they can still be an excellent source of targeted traffic to your site.

Sites are ordered by approximate number of members, from highest to lowest, but some of the sites with very few members can still have a decent bit of activity, so they’re worth checking out if your site fits in the category.
(If I’ve left anything out, please feel free to add it in the comments)

Web Development, Programming, and Internet
Users: 25,000
Submit: Developer related links
Users: 1,600
Submit: Anything related to software development
Users: 1,075
Submit: Web design related sites
Users: 825
Submit: CSS related sites and news
Users: ?
Submit: Web Development and design tutorials
Users: 300
Submit: Joomla related links
Users: 275
Submit: Anything related to Firefox and Mozilla
Users: 175
Submit: Stories and links related to the Erlang programming language

Search Marketing
Users: 6,100
Submit: Internet Marketing News
Users: 2,800
Submit: Stories related to Online Marketing
Users: 900
Submit: General Blogging and some blog marketing related stories
Users: 125
Submit: Blogging and Blog Marketing related stories

Users: 7.9 million
Submit: Stories about green living, health, human rights, etc…
Users: 5,000
Submit: Green news. Related to the environment.

Users: 325
Submit: Sports related news

Users: 2,536
Submit: Videos
Users: 9,500
Submit: Videos

Bittorrent and File Sharing
Users: 48,420
Submit: pretty much anything

Users: 4,420
Submit: Political news

Users: 1,470
Submit: Tutorials on pretty much any topic

Art and Photography
Users: 1225
Submit: CG art
Users: 525
Submit: Photos
Users: 450
Submit: Photos
Users: 275
Submit: Art

Science Fiction
Users: 500
Submit: Science Fiction News

En Espanol
Users: 50,560
Submit: (any Spanish speakers want to help me out?)
Users: 1,825
Submit (Again… Spanish speakers?)

Users: ~6,000 ?
Submit: Pretty much anything
Users: 825
Submit: Pretty much anything
Users: ~620
Submit: Pretty much anything, but you must be a myspace member
Users: 175
Submit: pretty much anything