Used to express the act of squinting. Originated from a chat that Kona-chan (the blue haired girl from Lucky Star) had with her teacher online while playing an r.p.g. with her. Usually used by Otaku's or obsessive fans.
Person 1: 3_3 That font is so small i can't see anything!
Person 2: Not really, maybe you need new glasses?
Person1:Maybe...maybe. Thank you, Person 2!
Person2:Your welcome, Person 1!