In a market where supply grossly exceeds demand, prices fall, and value is destroyed. This is an unhealthy market, and these conditions can apply to knowledge as well as to commodities.
A commodity where supply far exceeds demand is a devalued commodity. Maybe supply will stimulate some demand, but most of the time you just create an oversaturated market, and you end up dumping surplus stock at rock bottom prices.
We saw this in the European Union, where farmers were paid to produce more wine and butter than the market needed. To keep prices stable the EU had to stockpile the produce, these stockpiles being referred to as "butter mountains" and "wine lakes". This was not a sustainable solution.
On the other hand, what happens when demand exceeds supply? Prices rise, and the value of the commodity increases. A commodity where demand exceeds supply is a valued commodity. Almost always demand will create supply, and you will end up with a vibrant marketplace.
These situations apply to knowledge as well as commercial commodities.
An oversupply of knowledge (full databases not being used, loads of stuff filed and not read, loads of blogs with no readers, "knowledge lakes" and "knowledge mountains") devalues knowledge. Its seen as "a waste of time to capture all this stuff". "Why bother? Nobody reads it". Knowledge sharing, without knowledge reuse, quickly becomes a low-value activity.
An overdemand for knowledge (lots of questions on community forums, lots of people searching for answers, lots of expert opinions being sought) may cause frustration if the sought knowledge is NOT found, but certainly raises the value of the knowledge which is unearthed. Initially the bulk of knowledge which is found is tacit (people find knowledge through asking people), but this level of demand will cause increasingly more knowledge to be documented. Once the expert has been asked the same question frequently enough, he/she starts an FAQ, and the supply of explicit knowledge starts to grow as well.
If you are creating a knowledge marketplace in your organisation where knowledge can be exchanged and re-used, beware of the Knowledge Oversupply trap.
It may be tempting to focus on knowledge capture and on knowledge sharing, and on creating knowledge bases with lots of content. However unless there is an equal focus on knowledge seeking and knowledge re-use, you may just be dumping an oversupply onto an uninterested market, resulting in devaluation of the commodity.
Make sure supply is balanced with demand, and a call for "knowledge sharing" balanced with a call for "knowledge seeking".