To understand the commercial intent hidden in the keywords that people use when they search in Google it is good to think about the process of buying something you’ve never bought before. Usually if someone is using Google to help them in the buying process they go through three phases.
Initially they tend to start by looking around to understand what’s available using fairly generic search terms, then as they understand what’s on offer, their search terms get more specific. Ultimately they may start to look for specific products or services and compare competitive offers.
For example, let’s say that you were looking for a software solution for your accounts. In phase one you might search for ‘accounting software’, in phase two you might narrow it down and search for ‘Sage’ and in stage three you might look for ‘Sage reviews’.
Whatever your market, there may be a similar movement of the search terms from the very generic to the very specific. As potential customers use more specific keywords it is worth assuming that they are closer to making a purchasing decision and therefore the search term they use has greater commercial intent.