Got a text from this number and they actually referred to me by my real name. After I replied "who is this?" I got a text saying "a.dd me ony! IM.. id is giannagirlie". Then I replied "now cell phones get spammed too? great" and after that I got a reply "sry I have no reception"
Obviously trying to phish you into adding them in your Yahoo! IM and probably send you viruses or who knows what.