I may be late to the party on this, but I just noticed that Yahoo! is recognizing keywords that are formed using TLDs. For example, I have a website with the TLD of .st – mode.st. That domain is intended to convey the word modest. If I do a search in Google or Bing – one that lists my domain the SERPs – it doesn’t highlight my domain. However, if I do a search in Yahoo! for modest living, the word “modest” is highlighted. Not only that, it has a first (and secondary indented) ranking. That leads me to assume that they are not only recognizing it, but they’re also factoring it into their algorithm.