2. Block accounts the send out the same URL multiple times
3. Block tweets that contain multiple, popular hashtags
4. Block accounts that send multiple messages over a short period of time with the same hashtag
5. Allow users to flag accounts for review
6. Implement SURBL for URLs
That could be overkill...
> 3, 4. Block tweets that contain multiple, popular hashtags. Block accounts that send multiple messages over a short period of time with the same hashtag.
So, would you block these? “OMG I TOLLY FELT DAT #earthquake #sf”
“Someone at the corner of XXX and YYY? Baby crying under rubble #earthquake #sf”.
Why not a simple spam filter like the ones for email? Google seems to have a pretty good one now - a similar technology could be trained on tweets. Maybe not block, but just increase their spam score? A good filter might even figure these rules by itself.
2. Tinyurl could help them, but also there's a million affiliate programs out there, you could paste a different affiliate link each time. Also surely a lot of accounts legitimately contain links from the same domain - eg new blog posts.
3. This example was using hashtags, but also just popular search terms - "american idol". I don't see how you can detect that easily.
4,5. Agreed, those I think could work well
Other possible (negative, antispam factors): ratio of following to followers, number of duplicate or near dupe posts, etc.