Can you tell whether someone's smart or dvmb from the kind of posts and comments that they make? Or the conversations that they have?

I dunno. Youd never guess I teach grammar 🤣

I can tell what species of catfish they are. Catfish are not very smart.

Yes, either dumb or willfully ignorant. While I have great compassion, and patience for those genuinely afflicted with some mental slowness, I have zero tolerance for the acting dumb and those willfully stupid, or lying. They get blocked.

The more person responds in memes the less intelligence I assume they have.

I think it's very apparent and even intuitive to an extent but I believe it is limited to whatever the person's own limitations and prejudices are as to whether they can feel the full gravity of someone's intelligence.

It doesn’t matter if they are smart or not, you can get an idea of what they’re interested in….

I know how to assess myself, I come across dumber than a doorpost. Not too fussed about it tho

i can get a general idea.

I think you can get a pretty good idea. Especially when there are many spelling mistakes and the sentences are not complete.