The technology itself is probably not that difficult to build. The difficulty is launching a robust two sided marketplace. Now that there are already existing t

The technology itself is probably not that difficult to build. The difficulty is launching a robust two sided marketplace. Now that there are already existing two sided marketplaces in this space it makes it even more difficult for a new entrant. In the same vein, building a social network isn't that difficult but getting a huge user base to generate network effects is extremely difficult.