I think word of mouth affects peoples' decision a lot. I, for one, have bought games I wouldn't have considered getting before because someone thought so highly of it that they recommended it to me

The opposite works too, you warn someone about a faulty/bad product and they stay away

But this kind of thing is pretty hard to utilize in marketing, the product itself has to be good enough that people recommend it, and the person recommending it has to be someone you trust

Someone suggested Might & Magic: Clash of Heroes (DS) since I liked turn-based strategy games. I loved the game and played it like crazy till I beat it.

I try to spread the word about Nintendo but usually I get frowned upon faces from guys my age or younger.  It doesn't bother me that bad consider I've seen it around since about the 16-bit era. I can talk to women about Nintendo although some might see it as dorky but the others that are older and have kids find some of my recommendations possibly helpful.  I wish there was a rule that you couldn't talk shit unless you grew up during either the Atari 2600 or NES.

I remember I was talking to my friend about the all-holy Super Mario Galaxy when his little sister (who was busy shooting people in Uncharted) goes "Mario? That's for little kids" ~*She was like 12 or something XD