I see it being a new play toy for Google users for now.

It is always possible that they will test other ideas later on down the road for what it could be used for. Every good idea has to have a base to work off of. This might not be any different. It definitely won't be allowed to have any impact on search results as of now. There would be no way for Google to be even close to prepared for what would happen if it was used to rank sites.

Could you imagine if comments where allowed on ranked site? lol
I think all you have to do is see a few comments for videos on YouTube. It can be the coolest video in the world and you will still have a bunch of teenyboppers saying something dumb about it.