Spam filtering for Twitter

I decided to start a list of spam resources for Twitter, until now, I have the following:

• first of all, I have started to draw up a preliminary request for spam filtering features in Twitter itself or in the clients and requested them on getsatisfaction (Twitter) and uservoice (Tweetdeck)
• Tidytweet.com is a service to filter Twitter feeds, currently in private beta, looks pretty good
• you can set up Twitter filters with Yahoo Pipes easily, I have created a few examples for this, that I will put up here later
• Tweetblocker.com (looks ok, but is very picky about follower ratio)

if you know more spam resources for twitter let me know
twitter.com/alexlehm