At the top of my phone, in the status bar, i have noticed a weird new symbol. at first I thought it was the wifi connected icon. But its not. Its made up of four small squares, but sometimes a few squares disappear, and some times, red squares are added at the top. Any idea as to what on earth this could be, or what application has put it there? (its located to the right of the wifi icon.

Its pretty hard to explain without a pic. Thanks guys!