WP:WEB

I don't know what you mean by jumping to conclusions, but noted nonetheless. To address your example directly, Dominic Deegan was actually printed, published, and released, which gives it a  bit of a foothold in the webcomic world. It has tens of thousands of Google hits, the first several hundred of which are unique and relevant, and several hundred unique sites also link to it. It also gets a couple million views per month according to Alexa.com. The three methods on their own are not always the best for rating the notability of a subject, but when combined, they give a clearer picture

Some articles are marked for deletion soon after creation, and others aren't marked until several months (or years) after their first edit. However, in the end, they will eventually receive the same scrutiny all other articles must undergo- an unencyclopedic article will not be allowed to exist on the premise that other unencyclopedic articles already exist; they will, in all likelihood, be deleted eventually as well.

As for WP:WEB itself: It's a guideline used to help determine the notability of the site. While the majority of sites that do not meet the criteria are deleted, all of those that do meet the criteria are kept. This criteria is an extension of the following policies:

 Wikipedia:Verifiability
 Wikipedia:Neutral point of view
 Wikipedia:No original research

The following guidelines:

 Wikipedia:Cite sources
 Wikipedia:Reliable sources

And the following tests:

 Wikipedia:Search engine test

Basically, if the site has independent material published about it, receives an award, or is distributed through a notable publisher, information about it can be verified and, most importantly, neutral. This avoids original research. This also allows us to cite reliable sources; Wikipedia is not a primary source or publisher of original research/information. WP:WEB is basically the condensed version of several other policies and guidelines aimed specficially towards websites.