Imagine a website where you can find people in your area interested in playing sports. You could also sign yourself up as a player for a given list of sports, that you would be happy to join other people in playing.
An important point for this service would be that there would be no friction at all for finding people or signing up as looking to play yourself - no need to register, just search right away. (This is a pain point I have with so many services... it seems like login barriers are so mainstream and so unnecessarily so)
The thing is, how would you monetize something like this? It's not like a job board where companies have a budget for advertising their open positions, it's a personal sports board... How would you do it?
Do you want the easy answer or the right one?...
It's easy to put up ads and try to sell equipment and gadgets...
You might make way more from creating organised sponsored events like creating a league/competitions after you have an audience...
Also there are companies who really want to be associated with sports like some drinks and fashion, they have the budget to sponsor the entire site if it's good ...