federico - 3:13 pm on Apr 17, 2006 (gmt 0)

A number of sites seem to have a parallel appear/disappear pattern everytime Google updates it's technology beyond the normal monthly updates.

So for example, after both Jagger and Big Daddy, these sites fall out of the SERPS entirely and get zero (0) traffic from Google.

I happen to be one of these Webmasters and wanted to trade insights with others. Our main speculations currently are:

1. sites are filtered out because of non-www url is not 301'd to www url

2. sites are filtered out because they feature vanity domains (2nd, 3rd domains that point to main domain) and thus create duplicate content.

3. other algo "violation" that compounds with 1 and 2

thoughts anyone?