Namco Bandai shared more info regarding the partner system in their upcoming PSP title, Sword Art Online: Infinity Moment.
Asuna, Leafa, Silica, Liz and Klein are some of the characters you can partner up with in Sword Art Online: Infinity Moment. You can even choose random characters walking around town to be your partner. There are more options since you play as Kirito and can decide on which routes to take, not being restricted within the original story.
Going on adventures and quests with your partners will develop stronger relationships, which can lead to closer friendships and even dating.
Kirito can have late night talks with Silica or go walks with Asuna.
Get to know your partners, as you communicate with them on and off the battlefield. You can take them out to parks or go for coffee. There are plenty of other activities out there, for you to enjoy with your partners.
Once you befriend a character, you’ll be able to register them as friends and exchange emails.