Stickers

On mln, stickers are obtained by stickers are used to show creativity and get clicks on a sticker module. some even unlock cool backgrounds!
 * 1) buying them at a sticker shoppe
 * 2) asking a networker "'gimme a sticker"
 * 3) putting in a b.i.o.code
 * 4) something with the s.p.a. sticker vault (i don't know much about it)

more info