Question
We're trying to validate legal professionals as a segment via AdWords for our app that synchronises document viewing across multiple iPads. (no need for projector or hanging over shoulders, it also works remotely via VoIP).
Answer
Adwords is not the best platform when you want to target an "audience" instead of search terms. I would suggest you to use Facebook - targeting lawyers - or may be display ads - targeting pages visited by lawyers - and call out your app details in the ad copy. This will make sure that the persons clicking on the ad are from your target audience and are interested in what you have to offer.
