In versions of messenger that display a dot-dot-dot symbol while users type such as Facebook messaging, to dot-dot-delete is to start writing something and delete what you have written before sending it. The dot-dot-dot symbol disappears, leaving the other person wondering what you were writing, why you deleted it, and whose turn it is to say something.
"Dylan dot-dot-deleted me and I just know he was thinking about asking me out."
"Yo, I was chatting Annie and it was going great but then that bitch dot-dot-deleted me!"
"No way, man! Did she say anything then?"
"Nah and I wasn't about to so that shit just ended the conversation!"
"She was annoying me so i dot-dot-deleted a few times to freak her out."
"Hah. Scurr."
dotdotdot is the oral form of "..." People who talk as if they were in a chat room in real life use this word for expressing how stupid their friends are or for saying something stupid and pointless and should be slapped for even talking like so.
It can also be said as "dot-dot-dot" but the odds people these days are going to bother saying "dash" for the "-" are incredibly low.
Dan: I LIKE TO DIP MY BREAD IN COTTAGE CHEESE!
Mandi: LIKE OMG THAT IS SO KEWL!
Jim: dotdotdot
Dan: U R GHEY!