The whole point of a personal recommendation is you're introducing people you know are good to people you know and trust you. What's the value-add by inserting

The whole point of a personal recommendation is you're introducing people you know are good to people you know and trust you. What's the value-add by inserting a new app into the process, that charges one side? LinkedIn works because you attract supply (e.g professionals) with the draw of getting the personal recommendations/network effects for free and then make money off demand (e.g employers/recruiters) by letting them pay to win and send you spam. Two-sided marketplace businesses are supposedly the hardest to get off the ground. Especially if you're trying to charge for something that is currently offered for free.