I suppose it is to do with the previously coined #estonianmafia hashtag by Dave McClure as per my TechCrunch post in 2011 http://techcrunch.com/2011/10/11/startup-sauna-puts-estonian...

The Wise Guys name is a light-hearted attempt to communicate the fact that the Estonian and Baltic startup communities are infiltrating the world and yes, this comes from Dave McLure's coining of the #estonianmafia hashtag on Twitter.