For brainstorming, organizing links/resources and collecting research.

OneNote
previously recorded OTF Connects webinar Onenote for classroom collaboration
Padlet
works on most devices in the web browser
Sample:

Livebinders
similar to a digital three-ring binder
works in many web browsers, there is an iPad and iPhone app, you can download an Android app here

Evernote apps and products make modern life manageable, by letting you easily collect and find everything that matters.
works in web browser, downloadable program for laptops, android app, iOS app