it can help certain artist, and hurt other artists.
rap is so oversaturated now, and as fans we are so spoiled now with the internet and shyt that we get bored and can just lurk youtube for 5 minutes to find something else that catches our ear for the next 6 months or a year or so.. i don't feel it was like that like 8-10 years ago.. i'd buy a cd and play that shyt all the time for like a year PLUS straight. now, its like a new album or artist catches my attention for 6 months then on to the next one. there's exceptions, but not many.
i think its a combination of how accessible music has became, and the quality. you have to REALLY stand out or be doing something "different".
someone like chief keef, the internet is going to help... for a short period of time, until we find someone to replace him. then its going to hurt them because catchy gangster rap without substance is a dime a dozen.
someone like..idk ab soul, he aint have nearly as much buzz on the internet, i don't think as a lot of rappers.. but it's going to help..because hes slowly building a loyal fan base, not a temporary one that is listening to his music for more than catchy beats, hooks, and ad libs. his fans aren't subconsciously looking for the next replaceable catchy rapper when that "shock value" wears off
it can be a blessing, and a curse.