
It is a simple implementation lexicographically sorting the feeds in ascending order. Nothing more. And we plan to keep it that simple.
In several discussion about the need of this feature the usual argument was about the feed lists being much too long and a specific feed to hard to locate. Sorting all feeds would speed up the feed lookup. To everyone having this problem: please use folders! Organize your feeds in topic folders, don't add more than ~10 feeds to a folder. Don't even start loosing the overview!
I personally do believe the sorting option shouldn't even be necessary. Using folders has too many advantages (recursive viewing, hiding read items) to not utilize them.
Nonetheless "Sort Feeds" is added to SVN trunk to be released with 1.7.5