When the return on investment of an idea requires the collaborative effort of multiple parties and there is no financial incentive, the idea is often not implemented. For non-monetary items, think of the return on investment like this: "Do I save or lose time if I do this?"Example
The Semantic Web is an excellent example of this problem. The idea of the semantic web is that if web pages were to be written in such a way that computer algorithms could extract useful information (like store hours), the time that elapses between coming up with a question and searching on the Internet to find the information one wants could be significantly reduced. One could search for a product online and find all the stores on the Internet that sell it, what users think of each store, and so forth. However, to make this useful, many stores would need to invest a significant amount of money to alter their websites. How can one store be assured that if they make this investment, that others will as well?.A Solution
I believe one solution to this problem is to demonstrate the usefulness of systems that exhibit this problem. If it can be demonstrated conclusively that the return on investment would definitely exist if a sufficient number of parties were to invest, perhaps the process could get started. I have no proof of this -- perhaps most people wouldn't care if they knew systems exhibiting this problem worked or not...