Number of players in Multiplayer modes
You can invite one specific friend to join you online, and though you may not invite other players once the two of you are playing together, you may bump - sometimes quite literally - into other people while taking part in the online modes offered by the games. For example, you and your friend could end up as bounty being chased by 2 strangers. A friend can help you complete the mission marked as co-op throughout San Francisco, but also assist you in the Side Operations, hunt Research Points hidden in the city with you, have your back while you run from the police and Bounty hunters, or take your picture when a selfie just won't do. Note that you'll need PS Plus / Xbox Live Gold Membership to be able to invite someone.