As a member of a fair few social networking sites I'm well aware of the act of trolling - that is, posting something that could be (whilst sarcastic or ironic) offensive or controversial in order to provoke a reaction. But when this has seeped into very mundane acts, such as spreading false rumours of a celebrity death on Twitter, or winding someone up on a forum... can it really be passed off as harmless fun?
Because I think a lot of us on here have probably been guilty of it at some point - replying to a thread we don't care about with "k" to take the piss, or spreading a meme that uses sexist jokes (lord knows how many kitchen jokes Facebook has to account for...)
So at what stage do you cross the line?
There's an example for all Tumblr users - there's this popular blogger called wwiao who regularly posts crudely-edited images of Lady GaGa and Madonna, citing Madonna as a rip-off of GaGa, but with loads of obviously ridiculous 'facts' (eg. the Vogue video ripping off Alejandro, which violates chronological order

) - of course, the majority see the joke. But then there's someone a little bit dim who'll reply "MADONNA IS DA BEST!!! SCREW U!!" etc.
And you have to wonder - what is exactly gained from this? And then I wonder if the person saying "MADONNA IS DA BEST!!!" is also trolling...

I think I just hate everyone trying to be a comedian. In addition to this - the rise of trolling is also providing a pretty decent mask for those who
are genuine racists, or misogynists, or anyone of a hateful disposition, to get away pretty much scot-free by just adding LOLOL or some other form of get-out clause.