A noobish sentence which meaning is ''There are no girls on the internet''. When a person uses this sentence, he is using an excuse to tell you can't do a certain thing to girls, that the girl he is pointing is a man in disguise, or that he or she is lying.
Person 1: Can't you stalk any of the other girls?
Person 2: What other girls do you mean?
Person 1: her
person 3: ....
Person 4: LIES AND SLANDER
DER R NO GIRLZ ON TEH INTERWEBZ
Person 1: I wanna date this girl on the internet.
Person 2: you can't
Person 1: Why?
Person 2: DER R NO GIRLZ ON TEH INTERWEBZ!