Re: monetizing the service to generate revenues
I remember this kind of techno-utopianism from the 1990s. There's a good argument for Youtube - without Youtube there would be no Cyriak, no Alantutorial, no Glozell Green etc. But Youtube is heavily monetised and indeed the site's leading content providers rely on this monetisation to become Youtube millionaires. It makes whores of everybody, but that is true of life itself; some whores are more entertaining than others.
Besides, you're talking about art as if didn't have a commercial dimension. Art has always had a commercial dimension. Van Gogh didn't sell many paintings - but he did try to sell them. He took commissions and would have been thrilled to be exhibited in a major gallery. We know his work today entirely because it is commercial exploitable - the same is true of Vivian Maier and Bill Hicks. They achieved enormous audiences after they died because they were marketed effectively, and also because being dead the rights were cheaper.
Without the competitive pressure of having to make money you either end up with floods of weak crap, as per DeviantART, or you end up with esoteric stuff that exists in its own little world; which is fine, but the major visionaries of this world are tough people with iron wills, they take what they want. They exist outside the real of discussion.
Twitter and Vine as a vital creative platform / archive for future cultural commentators is a hard sell. The 140-character limit is horrible. Perhaps some writers can thrive with that constraint; but only a handful. In the long run Twitter will go the way of fanzines from the past, or the letters pages in old newspapers. All of Twitter might be archived somewhere, but no-one will read it and historians will skip past it because it's just random noise.