Collecting Tweets: TwapperKeeper

I’ve recently become interested in tools for collecting and analyzing Tweets.  I know that DiscoverText, which I’ve mentioned before, can be used for these purposes, and I’ve just begun experimenting with TwapperKeeper.  TwapperKeeper is, as far as I can tell, a free tool that allows you to create archives of Tweet data associated with hashtags, keywords, or @people of your choosing.  Unfortunately, TwapperKeeper can no longer be used to export the data it archives, since this apparently violates Twitter’s Terms of Service, as I learned through Mark Sample’s ProfHacker blog.

What alternatives are out there for collecting and exporting Tweet data?  Any suggestions and/or recommendations?