lucy24 - 9:28 pm on Sep 19, 2012 (gmt 0)

Is your number of indexed pages about the same? Is there a corresponding jump in the number of pages "ever crawled"?

Does Google just recall old URLs from time to time and simply adds them the the tally? Or invent their own?

Invented pages can't count here, because if it can't find the page it can't crawl it. Old URLs, yes. This is a pretty new wmt category-- only goes back, what, a month or two?-- so they're still pulling in information. The "ever crawled" category also includes pages you've moved and/or renamed. So anything with the pattern

oldname > 301 > newname

will eventually settle down to
pages ever crawled: 2
pages indexed: 1
pages not selected: 1