It's the easiest thing in the world to do. Set up a new Twitter account. Message a bunch of artists, get a few followers. It snowballs into hundreds of followers. But really... you're a fake profile. Misleading a bunch of people into believing they are reading the thoughts of one of their favourite artists.
Fortunately we have these things called phones which allow us to ring up said artists and ask them if they have a new Twitter account.
That's what happened last night when "@Big_H_Bloodline" tried to get myself and a bunch of other people to promote 'his' new Twitter account. 2 phone calls later and I could confirm that Big H does not have any Twitter accounts. You can add him on Facebook though 'Bloodline Bricklayer'
But yeh, impersonating people on the internet is NEEKY AS FUCK. Don't do it kids. Just buy their t shirt instead. You can spit their lyrics into the mirror and pretend you are them in the privacy of your own home and save yourself the embarrassment. BIG HOOLIGAAAAAAAAN!