I am considering starting to play Grim Dawn, it looks good but I wonder...:

1) Are there many people playing it? Is it easy to find groups?

2) Are items in game tradable/sellable to jsp? Is there any kind of a Market Place or something?

There is groups. Not TO hard to find
But no no item have trade value whatsoever the game incorporates mods even on the online play. Meaning people can spawn in any item they want at anytime which makes trading 100% useless :/

Pretty much this. It’s more of a solo play game.
The modding is good, so u can test builds at end game, so you don’t waste a lot of time leveling to 80-100 to realize the builds shit.

it is a sick game have 800 hours and still playing it

multiplayer = diablo 2 open bnet

so its no closed connection to a server its open bnet

the game itself is one of the best after diablo 2 - but singleplayer and coop only (or play with random guys in the lobbies you create like on open bnet)

Garbo game. Play Poe