Related to this, since I've used Bing Maps 'My Places' for years now, I've always wished (from the day the Photosynth Bing Map App was released) that if I was signed into Bing Maps with my Live ID that the Photosynth App would open up with a few more choices, such as:
:: to see all of my own geotagged synths on the map
:: to see all of my favorited geotagged synths on the map
:: to filter those two categories by time and a geographical location
As Joscelin points out, if I have already authenticated myself to Bing Maps via my Live ID, it would be nice to have my lists of geotagged synths and geotagged favorite synths synced to my Bing Maps 'My Places' as well - perhaps separated into two separate 'collections' as default, with the ability to move them into other folders without duplicates being made or their location in my collections changed at the next sync.