How can you tell someone's a troll?

I'm not sure.

so am i 

Trash talking all the time. 

Trolling is who trolling do.

BTW, everyone, please do not identify in a large club or in public whom you believe are trolls. That would be a form of trolling.

true

Annoying, unwanted, irrelevant comments.

People who vote to resign or offer a draw in the first 10 moves of a vote chess game.

People who request a vote chess game and when you create it, they don't join.

I’d also add that trolls can be people who make divisive comments that add nothing of meaning to the conversation  and are meant to cause arguments among the group.

arguing with an idiot makes you an idiot.  Call out Trolls!  Makes you a troll?  "How can you tell someone's a troll?"  Isn't the better question:  How do you stop a troll?

"How do you stop a troll?"

For any trolling which may have broken TOS (Terms of Service), report to chess.com. Other options is to block or ban from your club.

Don't feed them. 

Sadly, you cannot defeat trolls on the internet. You get rid of them they just pop back up later under a new name or new identity. Only real plan is, as Donna says, don't feed them.

Simple, ask them whether they are trolling, ask clarifing questions.

If you dont get proper answers, you are either being trolled or there is communication barrier due to non-native languages. In either case, you dont gain much from keeping to interact with said person.

Btw, it is always perfectly fine if YOU decide for YOURSELF that you dont want to engage with someone. Even if you cant/dont want to name a reason.

Try also to think before your post yourself.

In other words, maybe trolling is not binary but more of a continuum? I recommend that we all reflect on the the posts we make before posting. 

See also:

https://www.chess.com/clubs/forum/view/guidelines-for-personal-interactions-2