I am sure the market is not big enough to sustain them all and over the next year or two at least one will go belly up. The principle underpinning these sites is a good one - if you are looking to acquire technology you can search them to see what is on offer. On the other hand, if you want to make your IP earn its keep better you will be able to upload details of your technology to these sites, whether it be patents, know-how or a combination, inviting others to take licences. You can restrict the licence-out field to ensure you are not giving your competitors a helping hand. Then you may find a licensee interested in using the process in other fields e.g. for ceramic insulators - generating you royalty income without affecting your market position in plates and dishes.
Many companies dismiss the idea of licensing-out technology without really giving it enough thought.
I am not convinced the same applies to smaller companies. It is early days yet, but there are lots of technology transfer dating agencies to choose from. Cutting through all of the marketing hype I have extracted the main points of each of these three services into the table below and include my conclusion at the end. Please note that the precise terms of business with these companies are very fluid. In some cases they change from one day to the next and there is a large negotiable element as they increase their understanding of this new marketplace from customer feedback.