Accounts are a feature added in the Log and Load update. Accounts display a registered player’s stats. On the main page of surviv.io, in the top right corner, there is a link to take you to the stats page where you can view your and other player's stats. You can also check the leaderboards there too.
Overall Stats - These are displayed to the right of the player’s avatar. They tell what the player’s average kill-death ratio is, how many games they have played, total wins they have (all game mode wins count), and how many people in total they have killed.
Rating - This has not been released yet. It is said that rating will be based on your match placements and how many kills you get for each game mode.
Game Mode Stats - These are displayed under the overall stats. They give a detailed report of how well a player does in each of the 3 game modes (Solo, Duo, Squads). Aside from displaying the basic stats like the ones from the overall stats, they also give the win percentage, most kills ever gotten in one game, average damage dealt in a game, most damage ever dealt in a game, and average amount of time survived in a game, and total amount of rounds played for each game mode.
Match History - These are displayed under the game mode stats. They give a very detailed look at every round the player has been in recently for all game modes, or for each individual game mode. They tell you how long ago the player played that round, what game mode it was, how many kills they got, their placement in the round, amount of damage dealt, amount of damage taken, and amount of time survived. If you clicked on the arrow on the right most side, you get to know what place every single player got in that round and check their accounts if they have one (players with accounts will have their users in green). While there, you can also see what the player who's profile you are on killed in the round, their names have a crosshair next to them.