Dear Google – what’s with the apostrophe and +1?
Google has launched its +1 button - you'll see it just above here. But at the same time it seems to have thrown its grammar book out the window.
Observe that screenshot. It talks about a +1. And Google talks about "the +1 button". Yet its headline is "See +1's" and the example from the Google results is that someone "+1'd this".
No apostrophe is needed in these last two examples. The plural of +1 is +1s. And if I did a +1 then I +1ed. Or possibly as one ends in an e already, maybe I +1d.
At least the on-site +1 answers the question of just what it's for.