The New Yorker, in a piece on graffiti artist so-called "Banksy", touches on the issue of so-called pseudonyms:
The creative fields have long had their shadowy practitioners, figures whose identities, whether because of scandalous content (the author of “Story of O”), fear of ostracism (Joe Klein), aversion to nepotism (Stephen King’s son Joe Hill), or conceptual necessity (Sacha Baron Cohen), remain, at least for a time, unknown.Perhaps the best comparison the relative status of graffiti art and blogging is this assessment of Banksy from the Guardian, "[H]e's often feted as a genius straddling the bleeding edge of now. Why? Because his work looks dazzlingly clever to idiots. And apparently that'll do."
Anonymity enables its adopter to seek fame while shielding him from the meaner consequences of fame-seeking. In exchange for ceding credit, he is freed from the obligations of authorship. ***
The graffitist’s impulse is akin to a blogger’s: write some stuff, quickly, which people may or may not read. Both mediums demand wit and nimbleness. They arouse many of the same fears about the lowering of the public discourse and the taking of undeserved liberties.