Art

Biography

Chicago

Career and College

Countries

Elections

Full-text Books and Periodicals

Health/Medical

Immigration

Maps

News

Government/Politics

Reference

Spanish Language Sources  

Statistics

Think Tanks

Brainstorming/Mindmapping
Mindmeister
Creately
Bubble.us

Cartoon/Comic Creators
Creaza Online Comic Tool
Create Your Own Comic

Communication/Collaboration
Wallwisher -- Online notice board maker or bulletin board
Wikispaces
Tagxedo -- Turns famous speeches, news articles, slogans and themes into word clouds

Images
PicMonkey -- Photo editor
Cheezburger LOL Builder
ipiccy -- Online photo editor

Organization
Delicious
Evernote
Diigo
LiveBinders
Pinterest

Presentations

Google Sites
Glogster -- Online posters with music, photos and videos
Prezi
VoiceThread
Museum Box
Create an argument or description of an event, person or historical period by placing items in a virtual box.

Video Creation

Animoto
Muvee Cloud
Blabberize -- Make talking images
Voki -- Create speaking avatars
Go!Animate
Xtranormal
Voxopop
Dfilm2.0

Websites and blogs

WordPress
Edublogs