This blog, before I bought the domain FusionGrokker.com, lived at http://tuttletree.com/NerdFusion/ -- a subfolder of my family blog. While there and operating under the title "NerdFusion," I setup FeedBurner using the same title, NerdFusion. When I bought this domain and moved my blog here, I knew I would rather have my FeedBurner URL reflect my new blog title; but I also knew from past experience that changing the FB url causes problems. Doing so abandons any and all subscribers, and after you realize that, you can't get the old url back, because it's "in use" (by whom, exactly?!) So I just left well enough alone, and until today I have been continuing to point my RSS links to the old FeedBurner link.
In my mind, this is retarded because the whole point of using FeedBurner in the first place is so that you can change your blog domain or blogging platform without losing subscribers in the process. If they have the same problem -- albeit, not exactly the same, but close enough -- then what benefit are they really providing? Ideally, they would allow you to create an alias that points back to the original feedburner url, as long as it was unique and available. Heaven forbid the easy, correct method be available though, right? This started as an informational post and has derailed into a rant.
*Cough* Back to business.
So FeedBurner has some, erm, "problems." I would really recommend that you not change your FB url.
Instead, create a new one and have your subscription links point to it. Let your old readers continue to use the old FB url. It won't hurt anything, I promise. The only down-side I've found to this, so far, is that your stats are now split between the two. I'm not much of a stats whore any more though, so it doesn't bother me that much -- which is to say, at all. Half the time I can't remember my FeedBurner password, let alone feel like checking my RSS stats.
Now, my RSS link is what it should be: http://feeds2.feedburner.com/FusionGrokker/
I hope this helps prevent people from making the mistake of changing their FeedBurner URL only to find they have kicked their subscribers to the curb.