HTML Mark up effects Rankings
You know one curious myth I’ve always heard is that if your page is not 100 percent compliant that it will effect your rankings. This is not true what so ever, but yes its nice to have your website fully compliant with standard mark up, but it won’t effect your rankings any how or will it cause your rankings to drop any. The things you want to pay attention to is the crawl ability of your website and the structure of it.
When I refer to craw ability try to make sure the structure is laid out good, don’t have folder after folder cause generally page rank will just drop as your site structure deepens try to avoid such practice. The best thing to do is try to have all your files in the root then maybe a few inner folder, but generally on larger websites your going to have more inner folders so this can be an accept ion by all means. Some things to do though on increasing them deep links page rank is to build links to them, so it will pass through out the inner links. This is another reason why deep linking is very important, some people only focus on there home page, but quite honestly you should be focusing on your inner pages and building page rank into them too.