I thought about this. But there's a fine line between being tacky and being efficient. When I read bandwagon phrases like the one you propose, I always cringe. It's just not genuine.
I have a similar reaction to "you should follow me on twitter". Before knowing about this test, it possibly made me a little less inclined to like/trust you than otherwise. (I think it did, but I don't know how to measure that.)
I wonder if that's a common reaction: maybe there's an uncanny valley-type effect, where more efficient phrasings become turnoffs? Does the high conversion rate come at a cost of slightly alienating a subset of your readers?
