Hi Julian, interesting work.

Just a comment that supplements your concerns about the privacy part of a public tweet database: privacy isn't binary (it's not all or nothing) and it encompasses a right of self-informational determination. For example, the fact that a person shares private information on her Facebook page, which is accessible to 100 friends, doesn’t mean that she wants to share it with the world. I don't see how a public searchable tweet database will respect this right, unless the users explicitly and specifically provide their consent for such use

-- NikolaosVolanis - 26 Apr 2010