Twitter users are suffering through the service's growing pains. Some days, it's a pleasure to use. Others (like today), it's dog slow. Why is this? Is it an influx of posts from the new users that's crippling the service?
Only partly. I just spoke with people who know about Twitter's system architecture, and I'm told Twitter's growing Web traffic represents a manageable load. Rather, the service is getting crushed under a mountain of API calls that's 20 times the number of Web page views. These programmatic requests are from mashups that ping Twitter constantly, and apps that refresh their displays on behalf of users more rapidly than Twitter's Web pages would do on their own.
Eventually the Twitter team will have to put some governors on their APIs, and mashup programmers will have to design better-behaved applications. In the meantime, Twitter app and mashup users are making the situation worse. Or so I am told.