According to Wikipedia, "Web 2.0 is a trend in World Wide Web technology, and web design, a second generation of web-based communities and hosted services such as social-networking sites, wikis, blogs, and folksonomies, which aim to facilitate creativity, collaboration, and sharing among users. "
GooMedic.com has a summary on using Web 2.0 services for research which includes:
Social Writing (Documents) and Research Papers
Social Online File Storage
Social ToDo Lists
Web 2.0 as Research Tools 02-1- : Collaborative software. GooMedic.com, 02/2008.
Image source: ScienceRoll, a Creative Commons License.
Research Tip: Create Surveys and Databases with Online Forms via Google Spreadsheets
Google Docs & Spreadsheets Could Replace Word & Excel for the Average User. Clinical Cases and Images - Blog, 10/2006.
Video presentations: Novel concepts and easy-to-use web tools for researchers. European Molecular Biology Laboratory, 2006.