In planning poker, members of the group make estimates by playing numbered cards face-down to the table, instead of speaking them aloud. The cards are revealed, and the estimates are then discussed. By hiding the figures in this way, the group can avoid the cognitive bias of anchoring, where the first number spoken aloud sets a precedent for subsequent estimates.
When played online, members are together in a real-time estimation "room" or "session" and their cards are displayed on the screen. The same rules apply, but everything is more convenient and automated.
A planning poker session is usually around 30 minutes, and is led by a Scrum Master or team lead. The game allows each member to contribute to project planning and encourages lively discussions.
The game can be played with different card sets which denote story points or developer hours, depending on the team's taste. Card sets can be configured when the game starts.