Cool stuff, and I think there might be a software opportunity here. The idea is that enterprises empower employees to create their own tags for documents which are shared with colleagues to make stuff easier to find. E.g. the finance department can have their own tags that they share and understand which can be different to the tags that the sales department uses, or marketing uses, etc. This has the twin advantages of being cheap to implement and better than a one size fits all taxonomy.
Technically the challenges are in usability and linguistic problems (dealing with synonyms and words with more than one meaning – extreme e.g. one man’s ‘bad’ is another man’s ‘good’). This is where the software opportunity lies – although delivery will be best as a service.
From an investment perspective the challenge is predicting take up rates, ie. how quickly the market will grow.