Scissor Fobs are for hanging off one of finger holes on a pair of scissors...some people have a habit of losing/misplacing small embroidery scissors (like me) and if you put a fob of some sort on it, it can make it easier to find.

I found a pic, for an example

http://bp0.blogger.com/_nWC49VD-YM8/R041iEPs_7I/AAAAAAAAAZY/wM126I4AgTM/s1600-h/HPIM0063+(Medium).JPG