Looking at the domains playartifact.com and artifactarena.com, it seems they're parked by the same organisation, leading to the assumption that Valve's planning a Arena for their freshly announced Dota Digital Trading Card Game.
We just created this site to ride the hype-train for Artifact, the new game Valve just announced to be released in 2018.
The game was announced on 9th August by the The International 2017 panel in a break between two Dota 2 matches (announcement clipped on Youtube).
It looks like that Artifact will be a Free to Play (not really confirmed), Digital Trading Card game with a setting in the DotA / Dota2 Universe. Looking at the trailer below, you can guess that the colored elements forming the logo are symbolizing "strength", "agility" and "intelligence". We're looking into gathering more information wether it will be just a Hearthstone / MtG copycat or there will be yet unknown mechanics making the game as unique as we expect it from Valve.
There is not much so see, besides the colors of red, green and blue elements ("strength", "agility" and "intelligence").