Polls right now don't mean anything. We are in the pre-pre-game period. It's just "which name do you recognize" polling at this point.
I'd call it the "make a name before shit gets serious" game. And position yourself and your policies.
Some will probably drop out soon. Delaney, Gillibrand, Williamson, Inslee and Hickenlooper are constantly polling very badly without any improvements. I don't think they will last very long anymore. They might wait for the first debate and see the reactions, but if they don't improve from there I'm sure they'll see the writing on the wall, too.
I don't know what to make out of Messam and Ryan yet, they're not even named in most polls yet. And now with Swalwell, there's probably yet another for the "other" list, at least for now...
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454