I've never come across any evidence for this.
I think you're safe assuming it won't bring you any extra SEO benefits as it's something that anyone could do (regardless of the domain or content). You're best off focusing your energies into things that will certainly help: ensuring your pages well-optimised for your target queries, ensuring you've got lots of unique and regularly-updating content, and generating inbound links.
Your SEO success will not come down to hackery or doing clever little tweaks that give you some secret edge. It's just about lots of good content, organised in a way that makes sense for crawlers, and building as many links as you can to your pages with good anchor text.
Source: personal experience working with big sites