Yes, it’s YATPBP (Yet Another Twitter Performance Blog Post).
About 10 days ago, I turned GrabPERF loose on Twitter. Now before you accuse this of crippling the service and bringing it to its knees, realize that GrabPERF simply requests a document over HTTP about two times a minute. No additional requests are made for images and the like.
In the ocean of requests coming into the Twitter systems, the GrabPERF requests are like individual water molecules being added to the pool.

Twitter - Public RSS Feed, 1Day

The above graph shows performance for the last 24 hours. The purple dots are errors. Complete details, and a dynamically updating graph, can be found here.

Now that I have had a chance to show off, I will leave the Twitter team in peace. I am not a developer or a systems expert. I, like most people, rely on people with specialized skills to analyze and resolve the problem. There are many people on the Web who have taken on the challenge of reverse-engineering Twitter to try and determine how it does what it does, and how they would build a better mousetrap.

Ok. Go do it. Or shut up and let the Twitter team get down to the hard work of making this service work. Or volunteer to help them fix the problems.

The Twitter team has stated that they know how to resolve the issues that are at the heart of the performance issue. But as I said in a comment to @gapingvoid tonight, knowing what the solution is only makes up 15% of the application development process. Building, testing, deploying and verifying the solution takes 85% of the effort.

The Twitter team has a lot of work ahead of them. Buy them beer and pizza and let them get to it.