Small Updates
Alf Eaton: Aside: if you’re reading a Planet that contains HubLog, those posts will all jump to the top - sorry! (I wish Planets dealt better with small updates so I didn’t have to worry about it).
I don’t know what publishing software you use, but I see you provide an Atom feed, and Planet 2.0 and Venus both implement atom:updated as specified in RFC 4287.
More specifically, if you have a minor update and leave the updated date alone, the posts will not jump to the top. The next release of WordPress, for example, will contain the necessary hooks for a plugin to provide a simple checkbox for indicating that the change constitutes a minor edit.