Writers.

Money. A spot as US citizen to get into startup school.

Money. An investment from a noble mind to another noble mind.

Money. Pass information to fellows at YC (who are from a different domain, see YC as a cool place) they crowd and promote (seems organic)

Money. Well, then the product or the tech fades, because its a bloatware.

They retry the same thing again with next batch of people. Keeps the forum running. The maintainers get retired or really tired.

Readers. I have seen this one before. Reader. Well, now, you are old