A friend of mines just got accepted to be a contributor to Huffington Post. They don't accept too easily although he was quite lucky to get In. They don't pay you or anything but I assume it looks on a resume or something but does it do much for SEO? Like placing links in a post back to your site. He also told me that when he searched his post title, it came up on the search results. So it got indexed. Considering people have mentioned that contributors don't get their stuff indexed.