I don't normally like to post random "hey check this out" links - other people do that just fine, thank you. But after a quick look at Jing [1] i'd guess it screams out for use by virtual reference librarians using IM. From the Camtasia people, so you know they know their stuff, and it works on PCs and Macs. Check it out.

Heard about it on MacBreak Weekly 50 [2].