I miss the late 90s when you had a lot of small, independent websites. Sure there was always a war against spammers and scripts, but I feel like you could find more independent content from individuals instead of these big link aggregation platforms (remember web-rings?)
There is more to think about today when making something that hosts other's content (or links to that content). I'm surprised ActivityPub networks (Mastodon, Pleroma, etc.) haven't had more issues with spam and bad actors.
When starting a project like this, I think a few small things authors should consider right off the bat: implement some Captcha (preferably an open source implementation that's not Google mandated tracking, if you can find something decent), for at least account creation .. maybe posts too. I'm not sure what Lobsters uses for spam testing/filtering, but it'd be worth looking at that and other projects for any quick solutions. Prismo (https://gitlab.com/prismosuite/prismo) also comes to mind.