"My Apps" in App Market only showing SOME past downloads after a reformat? I used to be able to go to "My Apps" and view all my past apps.  Now that I've done a reformat, though, I only see a SMALL subset of the apps I've downloaded before.  I thought it was supposed to show all my past downloads?
Its been my experience that only paid apps remain in your my apps list after data is erased from your phone. I believe that the list of downloaded free apps is stores in the phones memory so its lost when you wipe it. This is the benefit of services like appbrain.

Edit: As thunsaker points out, if you use Google's Android Backup Service and you have a 2.2 or later device it will save the list of your downloaded app (among other things) and restore that to the Market after a restore.