[natrius]

"Obviously this would be limited to public tweets (no private tweets, no tweeting on the user's behalf, and no DMs)."

I don't think any of those limitations apply. If you can do something via a web browser, you can do it programmatically, depending on how much pain you're willing to endure.

[poblano]

Sorry, right -- I was just thinking of straight-up scraping of public pages. Asking for the user's password and logging in to do more scraping would probably be possible, but a lot more painful.