If you’re reading this post at randomguy3.wordpress.com, the title of this post will display as “Planetary Exploration”. If you’re reading it at planetkde.org, the title of this post (and, indeed, every other post by me) will be “randomguy3”.
You may have noticed this with several other planetary bloggers, by and large people who use WordPress. But not everyone who uses WordPress has this issue – Wade Olson, for one, gets his post titles displayed on Planet KDE.
The common theme, as far as I can see, is avatars. If you have an avatar, a <media:content> tag is placed in each item of the feed linking to it, with a <media:title> subtag. The Planet appears to pick this up (the title for the avatar) and use it as the title for the feed item (ie: the post).
I can’t check this for sure, though, since WordPress won’t let you remove your avatar, only change it.
I suspect using /feed/atom as the feed url (rather than /feed) will fix the issue as well, since that doesn’t make any mention of the avatar.