What is Alert The Internet?
1.
There are a few situations where one could yell this phrase, but the main thing is to convey sarcasm. For example if someone you know says something that seems utterly useless in a tone where they're trying to sound like it's the news of the year (and it really isn't), then you'd say this phrase in reply. See
(instant messenger convo)
Joe: holy shit dude omg i just asked out sally and she said yes *random emoticon* oh man shes so hawt
Jack: ZOMG ALERT THE INTERNET!!!~ lol dude i dont care shes prolly gonna hump u and dump u rofl
Joe: stfu *angry face* ur just jealous cuz u didnt get her u have no balls
Jack: maybe i should alert teh internet that ur a total douche lol
See