For a long time, I used Hootsuite to automatically post to Twitter whenever a new Wetpixel front-page article was posted. At some point, Hootsuite's broke when posting Wetpixel tweets; when readers clicked on the post URL, ow.ly would display an error page instead of going to the actual post ("Invalid GET Data"). Here are two examples. The first time this happened, I tracked the problem down to the way Hootsuite works with Google's Feedburner (which Wetpixel uses). Someone posted a fix on a forum involving customizing the way Feedburner inserts Google Analytics tags. I can't find the forum thread right now, but it was a simple fix and seemed to work... until it stopped working. At the moment, some combination of Wetpixel and Feedburner and Hootsuite breaks the shortened URLs that Hootsuite produces (via ow.ly). As a sidenote, I hate that ow.ly links load into an iframe. There is code to prevent that, but I'd rather add code just to deal with ow.ly. I've just suspended Hootsuite's RSS to Twitter service and have signed up for Twitterfeed (@twfeed), which seems to be reviewed favorably. If Twitterfeed doesn't work, I'll give this Expression Engine plugin a try.
Thanks, Giles, for helping with the service and plugin research!