The primary success of Dr. McNinja is that it doesn't rest on its laurels. Oh sure, it could get a fanbase just by having a doctor (who's also a ninja), but every week there's a new defining point of absurdity.
"I come from a race of sneaky lobster people."
"Knife Eye Attack!"
and so on
The big problems that deter people from interest in webcomics, namely Cerebus Syndrome, poor art/proofreading, irregular updates, and injokeyness tend to be things easily overcome if the strip is trying hard enough or has few enough of these problems. Unfortunately, Sturgeon's Law means a high probability of seeing the worst of the worst before you see the best of the best.
What this means is that to be a "successful" reader of webcomics you have to be able to read bad ones with abandon, follow linked favorites with no sense of self-preservation, defy the boundaries of the furry ghetto, ignore bad art... In terms of one's cynicism and level of expectations this is best left to the imagination, one must become a hardened snarker, an overly tolerant milquetoast "fan", or someone who just takes things as they come. Regardless of outcome, enough time spent in archive binges will mean that about the time you seriously worry about wasting your life you WILL find a few diamonds in the septic tank.
