These will be the best 'searches' you can get - forget confusion of double meaning words and searches which produce a load of gibberish. Yahoo! and others are working on producing a number of freely available tools which will permit all sorts of previously unheard of results.
Take Yahoo! Pipes. They have been around for a year or so and I have spent the last few days working out what it can do and how they work with other services. One of the modules is the semantic tag adding module form Open Calais which I have blogged about in the past. It is not quite there in accuracy (the Gnosis plugin seems to be more accurate?) but with a PHP output connected you have a really professional method of collecting web hits to rival almost any of the paid-for services out there. All you got to have is a bit of patience to knit it all together and customise the search functions. Pipes is really intuitive and once I watched a few tutorials on YouTube, found it quite straightforward and not at all daunting.
The tools for the measurement of social media are web hits and with the challenges this evaluation process presents you don't want to spend your time sifting irrelevant search results. All an analyst wants is a clean, relevant list of new coverage before setting to work deciding who has influence and what the content means. Don't rely on the semantic web (or any other computer system for that matter) to decide how good your coverage is, but when it comes to monitoring and low-level analysis it has a massive role to play.