Twitter’s advice when this sort of thing happens is to change your password, which I’ve done, but there’s another bit of advice worth paying attention to:
Chances are there are many applications that can access one’s Twitter account, especially if you’ve been online for a while and have tried new things. Among the apps that I discovered had access to my Twitter account were the following:
And several more.
In revoking permission for all these apps, I’ve locked the barn door as it were. I recommend that others also change their Twitter passwords and consider revoking permission especially for apps they don’t use. (Did I ever use Pinterest? Or About.me?)
Apologies to all those who got stupid spam direct messages from “me” as a result.