This is exactly like TrackItBack, which you've probably heard of? I came across them since they had some pretty awesome airline mile bonuses. I never used the stickers (I still have them); all I remember was thinking to myself "damn these are some expensive stickers." (The miles promo was so good that it made sense to buy them even if you wouldn't use them).

..

I just searched for them and found that they're out of business. Other competitors seem to be idstickers and foundit, though I know nothing of them.