A Friday PR didn't make sense to begin with but if Sean did imply releasing news on a Friday then one or two results can be achieved.  The news is released late in the day and it's so good that the news gets around to many and people think about it all weekend and come in buying on Monday. The other theory is they forget about it by Monday and it becomes just another 2012 PR.  Bottomline; whatever news is released it needs to attact buyers.