Consider that, once upon a time, to successfully creep on somebody you actually had to show up in person, or send mail, or something like this. That took time, and resources.

Now, I have to spend ~30 seconds slinging out a fast message to attempt and reconnect, and if I hear no response, I may do the same thing in a few hours--note that my time spent is less than two minutes/day, which subjectively seems perfectly reasonable. To the receiving party, if communication isn't desired, this seems like a huge deal.

Moreover, limiting only to a certain class of stereotypical male (the hacker), it's very easy to get in a situation where you mistake lack of communication for a channel problem instead of an interested problem, and so you resend over and over--especially if you think that hey, maybe the message got lost or something.

Compound this now with the way people leak information online all the time, and the way that these companies (in order to foster connectedness/advertising) practically rub information and personal data in our faces. A message out of the blue (because it's so easy to send) about a person's shared interest in a common album (because my social network provider told me about it) is immediately tagged as creepy, even though the data and message were trivially put into motion.

(I say this having made and sometimes still making these mistakes.)

I think that a new sort of manners need to evolve that actually recognize just how easy it is to communicate nowadays. People need thicker skin, and they probably need much more explicit flow control ("Not interested, fuck off." instead of silence). On the other side, people need to appreciate when they might be making others uncomfortable by spamming too much or doing too much cyber-sleuthing (which is, again, something that once took real dedication; "I remember when being a stalker used to mean something" lol).