Instagram is one of those apps that Microsoft's smartphone team seemingly had written off as likely to come to the Windows Phone platform.
In a December 2011 slide deck where the Windows Phone marketing talked about "ring fencing" apps that weren't on the Windows Phone platform -- and backing other comparable apps in their stead -- Instagram was one of those cited.
(Two former Softies developed an Instagram-like app known as Bubblegum a while back, but I've sadly never seen MIcrosoft do a whole lot to promote it. And there are a few other Instagram clones, like InstaCam, in the Windows Phone Marketplace, as well)
With the announcement on April 9 that Facebook intends to buy Instagram for $1 billion, maybe there's renewed hope for Instagram on Windows Phone after all.
Here's the thinking from some Windows Phone backers (that I saw via Twitter): Microsoft owns a 1.6 percent stake in Facebook. Facebook now owns Instagram. So maybe Microsoft can put (a little/a lot) of pressure on Facebook to get Instagram ported to Windows Phone. The photo sharing/filtering app is currently available for iPhone and, recently (and to the chagrin of a number of Apple users), Android phones.
Now Microsoft just needs Facebook to buy Zynga, Pandora, Urbanspoon, and a couple hundred more developers who are dragging their feet over porting to Windows Phone....