Apol's for the long post, I've asked this on a few SEO forums, and no one can give an explanation, so hoping I'll have better luck here
Until November last year, our indexing on
www.mylocalservices.co.uk was consistant, averaged 350,000 pages in the google index.
Then, and ever since it jumps all over the place. last week was a new record, site:
www.mylocalservices.co.uk returned 10,400,000 pages.
Sounds great, but its nonsense. The week before it was 70,000, and before that it was 100,000.....
This week its been sitting around 1,100,000 pages, and this morning it showed 55,000 pages, although refreshed just, and it shows 1.1 million again.
Throughout this, traffic and adsense revenue have been fairly consistant, although we show a 5% increase, its not what I'd expect from a 250% increase in listed pages.
Our sitemap is updated daily and webmaster tools reports the following:
Sitemap stats
Total URLs: 1,906,789
Indexed URLs: 733,560
which is pretty consistant.
I know Google has a multitude of different data centres, and being a directory, it may see some of our pages as duplicate content, but can anyone offer any rational explanation why the results keep bouncing so dramatically?
Or is the "site:" tag no longer worth using as a guage to indexing?