I fully expect the pace of new apps coming out of the Windows Phone 7 marketplace to decline over the summer before accelerating wildly this fall.  The reason is pretty obvious, developers are going to be turning their attention to the forthcoming Windows Phone 7.5 (aka Mango) rather than continuing to develop for Windows Phone 7.

While Windows Phone 7 was certainly a competent entry into the consumer SmartPhone arena, it is Mango that looks truly compelling.  For developers of both consumer and enterprise apps, Mango just has so many goodies that continuing to develop for NoDo doesn’t make a lot of sense.  Weak Windows Phone 7 sales means there is no need to stake out your territory now, while failure to have an app that fully exploits Mango when it ships this fall could leave you in the dust.  So developers are going to tend to finish up apps that were nearly done anyway and get them into the Windows Phone Marketplace over the rest of May and into June, but new starts or apps that are in the early stages of development will choose to target Mango.  That means we’ll see few new app submissions in Q3 (July, August, September).  Not only will new app submissions accelerate once Mango becomes available in Q4, I think the floodgates will open and the submission rate will dramatically exceed the peeks Microsoft as seen so far.

By the way, for those who wonder why Microsoft apparently won’t call Mango Windows Phone 8 there are essentially two clues.  The smaller one is that the OS kernel isn’t changing significantly, and that is a key historical justification for a new major release number.  The more important one is that Mango is more of a completion of the original Windows Phone 7 vision than a “what’s next” release.  You can even see this clue in the original name Microsoft announced, “Windows Phone 7 Series”  That proved to be so unwieldy that the “series” was dropped from the name.  But the concept wasn’t.

Sadly the next few months are going to be kind of boring for Windows Phone 7 owners.  But they are going to be extremely exciting for developers, and pundits.