Companies love milestones nearly as much as bees love honey, so it doesn't come as much of a surprise that Microsoft would take advantage of Build 2013 to announce as much positive news as it possibly can. This time, MS head Steve Ballmer has revealed to us that he expects the Windows Store to hit the 100,000 mark (in terms of total apps) sometime this month. Sounds about right if you monitor services like MetroStore Scanner to get a good feel for the OS's progress: it lists over 95,000 apps, which certainly fits the bill.
Additionally, Microsoft also claimed that the very same Windows Store has witnessed app downloads in the vicinity of "hundreds of millions." This vague indicator is not as impressive as it could certainly be if an actual number was attached, but we have a feeling that our friends in Redmond are trying to keep the specifics as hush-hush as possible.