Web 2.0 /Lib 2.0 may have its uses but I genuinely dont know where it fits into an academic library. Twitter might be of most use to let students know things quickly and its more readable and accessible than an allstudent email. If the network/email is down a quick tweet might save someone a journey into the Library. Twitter style of whats happening right this minute is good.

igoogle

Igoogle is a handy place to store all your tweets readers calendars and other stuff. So theres only one page to rule them all.

Federated Searches

Ive been looking at these for the last couple of days. I even built one. Its a bit like sewing bits of spaghetti together.

Have a look at this open source one http://www.vufind.org/