This is probably log file spamming. They're sending you fake referrals so they might show up in your log stats.

And the point is?

I imainge they expect me to click on the links to go to their sites do they?

Can I stop them? My bandwidth has gone sky high.

Just had similar for a site, fortunately the user agent showed, PycURL.
Quick add to the .htaccess it go bye bye.

I imainge they expect me to click on the links to go to their sites do they?

No, they expect their site's ranking to be increased when search-engine crawlers crawl your log. They are hoping your site is misconfigured such that your log is publically-viewable.

You can serve them up a 404 or better yet redirect them back to their own sites with .htaccess if you want ... let them eat their own bandwidth.
The easiest way to identify them is based on the referring url they're coming from, you probably can identify adult terms and block based on referers with those in their .com's also.
See:
Log File Spam .htaccess Block [webmasterworld.com]

Thanks, thats really helpful

"Can I stop them? My bandwidth has gone sky high...."

Seems you're only in the very beginning of the long and winding road the name of which is "Personal Sad WWW Experience Street". Have a good trip then!

Essex_boy I have exactly the same problem for a similar site - the only solution is to use something like modescurity and ride it out.

.htaccess blocking is not robust enough in this case. The referers, url's, ip's are very comprehensive, Each day about 20 new proxies are being used.

I wouldn't mind if it was traditional logfile spamming as this can be easily cleaned up or not logged in the first place. What annoys me is that the spammers are actively targetting scripts on the pages.

I have a login box newsletter signup box etc. The spammers see the links and automatically stuff the login and newsletter scripts.

This is harder to clean up and makes admin a bit more difficult.

Check out modsecurity.

[edited by: Frank_Rizzo at 9:34 am (utc) on Dec. 15, 2006]

BTW you will need the rulesets from gotroot. Modsecurity just does the basics. The extra rulesets are for blocking the trash you are seeing.