Incoming links - can someone affect your Google ranking with these?

[cazzzk]

Following some kind of penalty that our site received on the 6th October, and lots of investigation ever since, I've found a number of dodgy-looking sites which link to internal SERPs within our site (and occasionally other pages). These SERPs are blocked using robots.txt and a 'noindexed' tag.

Some SERPs are linked to up to 42 times from these dodgy sites. Is there a way these could have affected our site in Google's eyes? Having a look and some of the links in Google webmaster, they now go to 404 errors or the domain is no longer registered etc. but many still work.

Also, beginning back in about August, I started seeing nonsense sites turn up in Google alerts for our site's name minus the .com. The keyword was listed in amongst a load of nonsense words. The links to these sites took you through to one of those 'your computer is in danger! click here to check that you don't have any viruses' windows.

Is this part of a planned attack on our site? Have these kind of links caused a penalty from Google?

And is there any way to stop them?!

[edited by: tedster at 6:29 pm (utc) on Dec. 15, 2008]

[tedster]

There's no way you can stop someone from linking to your website. Matt Cutts recently addressed this question yet again - saying that in most cases today, inbound links placed by others from bad neighborhoods cannot hurt your site's rankings.

He suggested writing a note through WebmasterTools reconsideration request if you see lots of bad backlinks showing up that you did not create. In the rare case where such backlinks are causing your ranking problems, this can help.

Outbound links pointing TO bad neighborhoods are a problem for many sites, especially with all the server hacks making the rounds [webmasterworld.com].

And also very common is Google identifying inbound links that you have placed yourself (via paid links, partner sites, link networks, etc) and devaluing their power. Similarly, perhaps you had some backlinks from apparently strong pages on other sites, but those sites have now lost some of their power. Those backlinks would no longer give you the same benefit they once did.

So a ranking drop can be a simple devaluation of backlinks, rather than any true penalty.

[cazzzk]

Thanks for your help.

We're working on a couple of things I've found which might have caused our penalty, including changing old 301 links which used to exist as real pages but now all point to the same page (could be seen as trying to falsely boost that page?) to a 404 page with a message, checking that no page is over-optimised (although our content hadn't really changed much before the penalty), and making sure the 1000s of pages we have on the site as as unique as possible.

[tedster]

Also verify that your custom 404 page actually returns a real 404 http status (according to the server header, not just in the source code for the url). A so-called "soft" 404 page has tripped up many a site.