Just looking in google webmaster tools for some SEO clients and noticed that they are now showing thousands of pages on my site as links back to their site. The urls are all invalid blog ones: eg http://www.mykeblack.com/blog/index8f62.html/index451d.html?m=200910. These are invalid links to the blog section, but because the blog uses a custom 404 page, they are all showing up in the site's backlinks. One site has gone from having 298 backlinks to over 10,000 overnight.

There are two possible reasons for this: one is that google have updated WMT so that it now shows all backlinks not just the select few that you see in the link: query in the serps. The other possibility is that someone is trying to do some black hat SEO to try to get my site penalised. If this is the case, then it is not working and all those extra thousands of pages will actually improve this site's ranking rather than damage it. Google might just be experimenting with an updated backlink engine, so these extra pages and links might disappear before tomorrow anyway.

I'm going to do some more digging to see where the links to these blog pages are...