Many of you might have noticed hits in your referrals log from sites which are not linking to you. This is a known problem which affects search engine rankings severely and I will explain how. I didn't know where exactly to post this but it is crucial that the community is aware of this issue.
The trick is done by sites sending traffic to you with 302 redirects in the server header response. Now, when googlebot or msnbot visit the spammer's site and then there are 2 possibilities which I have detected.
The one is instantly sending the bots to your site with a 302 redirect
The other is by featuring a list of sponsored listings which have a few dynamically chaning links to various "sponsor" sites. They link to a special url in their site, which then sends a 302 server header response and the bot/visitor goes back to the site.
Now there are some networks which have thousands of domains on a few IP addresses, all running the same script. From what I can understand, they are aggregating their links from google results related to relevant keywords.
I have tried to block their IP addresses, but it does not seem to work for me. The following is what I have in my .htaccess (at the very top):
Order Deny,Allow
Deny from 216.34.131.
I am trying to block all hits from domains hosted in the 216.34.131.*** ip range.
It just does not work...
Then I tried adding this at the top: