I'm not saying it's perfect. But I've used it (multiple times), it works (well, eventually, I had problems getting a full archive). No, it doesn't include comments you've posted elsewhere. But compared with, say, Slashdot, you can actually extract _some_ of what you've written. I knock Google hard where I think they need knocking. DLF is actually pretty awesome, and one of their positives.

I was there then (actually, 1980s). I didn't.

Very good point on mandatory account creation. I'm trying to highlight the actives rather than the total profile count though. As in: what's the value of G+ as a discussion community.

Well ... that is an objection I've not yet encountered. Though as I say to all: the sitemaps are there. Grab a few and do your own sampling. (Previously mis-replied below).

There are good things Google does, one is the ability to export your user data, including posts. If you use this, export in JSON format, not HTML. You can use tools such as jq to export specific records, including your source marked-up text. This allows you to re-post content elsewhere (though that can still be work).

Thanks, but no, the results aren't bogus. What they do is measure what they measure (and what's measurable). In the case of G+, that's publicly visible activity. I'm looking at extending the analysis to include followers and views, where available, though Circlescope already provides much of that information.

Well ... that is an objection I've not yet encountered. Though as I say to all: the sitemaps are there. Grab a few and do your own sampling.