It could also mean that you're being texted by The Fonz.

Jock Dude #1: So she, like, texted me the other day and in it she put her "Heyyyy!" with multiple "y"s.
Jock Dude #2: Oooh, multiple "y"s! You know what that means!
Jock Dude #1: Oh yeah. You know a girl is, like, ready to go when she does that. There's a direct ummm... (searches earnestly for the word "correlation" but fails to find it) link... between the number of "y"s a girl puts on her "hey" and how much she wants to fuck you!

-- Line-up for bus passes, overheard by Mel