Why yes, I am going to mention every little advance from Google that I hear about; thank you for asking. I seems that Google now searches for synonyms – though it ironically knows no synonyms for synonym, nor for thesaurus. Just prepend any word with a tilde (~) and Big G (the other big G – the one that exists) will search for the word or its synonyms. To see only the synonyms, search for ‘~%s -%s’, where %s is any word.
Strangely, it seems to think that the only alternative for ‘frog’ is ‘froggy’, but a search for ‘toad’ yields ‘frog’. Don’t ask how I came upon that example.
Coolness aside, this could be useful for help/tutorials/guides/faqs which are all considered synonyms. And yes Google considers Sofa and Couch to be synonyms.