I've finally reached a point in my life where I can invest a bit more time and money into my hobbies. I'd like this to include a jam or two a year where I can fund cash prizes to drive interest. The first jam I hosted was loosely themed on the ps1 aesthetic (lame, I know). Most of the participants were my RL gamedev friends. As cool as that was, I didn't really see any broader interest. I know just injecting cash prizes won't really drive it either, as I've seen jams with prizes fail as badly as I did. 

My real question is, what kind of jams are people really interested in seeing? I personally like jams centered around a solid theme with a fair amount of rules to reign in the wild brainstorming my mind defaults to. I'm probably looking at doing this a bit closer to the holidays, so there will be a glut of jams already. Honestly if I don't get a huge turnout, it's really not a big deal. I'd just like to do something a little more interesting than I did last time and I'd like some opinions on which direction I should take it.

I've made games for some jams already and my guess about what makes a jam popular would be: community. Look at jams that take place once a year (especially featured ones), and how many people join each year. It would sure be interesting to also have insight on itch.io's traffic to make better sense of the numbers, but nevertheless, you'll notice jams that get increasingly popular year after year, or month after month (like indipocalypse). You might want to contact their organizers to ask them about their experience.

Although I don't know if that's the right thing to do, if I started a gamejam, i'd do everything I can to bring its participants together, make the jam a regular and consistent event and celebrate the creations that made it to the top (congratulations, youtube video, discord roles, help with whatever you do best, etc).

I hope that helps.

Cheers!

That does help. Though not related to games, other content creators and event producers all say that consistency is key. I guess then the idea would be not to pin my hopes on one event, but just try to do the best events I can consistently over a period of time.