Hey guys, A few people have asked why Favstar got blacklisted, so I thought I'd post this here to answer, and perhaps allow others to prevent this happening to their own service.
The reason given by Twitter for Favstar's blacklisting last Thursday was that it was [in theory] ignoring a high error response rate from Twitter, when it should have been backing off. This is undocumented, but Matt Harris has told me that if you see 10 errors per second, you should be responding with incremental back off. Implementing back-off based on rate limits alone is not enough. I'm seeking more details (timeframes, which errors, 10 out of how many requests per second etc) and will post them in this thread when I know more - unless Twitter does themselves. Cheers, Tim.