Not a poster on OMNI (not allowed to be yet - the perils of years of persistent lurking), but this type of implementation was what I was envisioning when I read the initial proposal. It would act as a means of indication to the poster without being a broad signaling mechanism to the community (beyond the reading of that specific thread and coming across a message that had a ton of likes). In theory, we would get a somewhat Skinnerian positive behavior reinforcement without the explicit ill will to others of a negative indicator (an "Dislike", for instance). Gamers or political likers could click to their heart's content with little systemwide consequence (spuriously making some posters feel good - the horror!), but some of the +1'ers would feel this is a good substitute and others who are silent (ahem, me) would click in support.

Perhaps the furthest I'd think it would make sense to go in terms of community signaling would be being able to sort a thread by number of Helpfuls/Likes. But even that is a bit troublesome, I'd imagine, because there's so much context to be gained by seeing discussions in order. (However, given that it would be an explicit choice a viewer could make, there's an argument for caveat browsor there.)