Sure, but by their definition someone who visits Google+ once and then never does anything with Google except search for the rest of time still counts as an active Google+ user.
Those people simply aren't engaged in any kind of social layer, and yet Google is reporting them as if they are.
It might not be correct to measure Google+ as if it were a direct equivalent to Facebook, but that doesn't make the numbers they are releasing any less misleading.
If Google+ runs as deep as Google seems to imply it does, anyone using Google search while signed in is "using" Google+. I know when I do searches, I get results based on what people I know have been sharing. If I search for "putty", my top result is the PuTTY client, because lots of Google+ users have visited the page or liked it or shared it or something. I can see under the search result how many people +1'd it.
I'd consider that "using" Google+ the way I understand Google+ to work. You don't need to use it as a Facebook in order to experience the "plus" in Google+ (criticisms about SPYW aside).
Ok, but that definition still renders the numbers meaningless - it's just a box you happen to see forever onwards if you've ever said yes to one of their prominent enticements to find out what Google+ is.
If they told us how many Google+ members use those results, and how often they are picked in comparison to the non+ results, that would tell us something that justifies using that definition.
As it stands, the numbers only tell us how many people clicked through a very prominent ad.
Those people simply aren't engaged in any kind of social layer, and yet Google is reporting them as if they are.
It might not be correct to measure Google+ as if it were a direct equivalent to Facebook, but that doesn't make the numbers they are releasing any less misleading.