Philadelphia Experiement time travel

The idea is that we learn of time travel with the Philadelphia Experiment. However, I believe we knew of it sooner. That said John Titor did say that Microsoft and Yahoo do not exist in 2036. Al Bielek of the Philadelphia Experiment says US does not exist in 2012.

Perhaps John Titor is right, because today Microsoft lays off 800 more workers. Well, guess win7 sales are bad - hasta la VISTA baby!