Filed under: CellphonesJust this summer we saw text messaging party down after turning 15, and now its time to get your weekend started right by celebrating 20 whole years of GSM. Reportedly, "15 phone firms signed an agreement to build mobile networks based on the Global System for Mobile (GSM) Communications" on this day in 1987, and while it took "12 years for the first billion mobile connections to be made," things have pretty much