Seems like is has been a reasonable bet given the numbers [3] but seems like a lot for a pre-release product.
[1]http://www.wsj.com/articles/twitter-acquires-live-video-streaming-startup-periscope-1425938498
[2]http://techcrunch.com/2015/03/13/how-periscope-works/#.fhzefvp:TKeD
[3]https://medium.com/@periscope/periscope-by-the-numbers-6b23dc6a1704#.ivtvmsx9n