To dot someone is to respond to his or her latest message with serveral dots in a row. He or she then becomes dotted.
The dot method is often used to show your lack of interest or displeasment. Common places for this method is Instant Messaging, IRC and mobile text messages.
When you see people fighting and one of the fighters is able to land successive blows to the face. All the welts and scars of the victim on their face means they have been dotted by the oponents fists.
A very common response to any sentence that includes the word "Indian". It is to distinguish the indigenous peoples of India from the Native Americans.
Intellectual person #1 "So I was talking to my Indian acquaintance last night...."