If we had mandatory security certifications, Reddit wouldn't exist. Nor, for that matter, would Windows. And while many of us would probably rejoice at that, I think a lot of people would be pretty pissed off if they had to use OpenBSD.
BTW, I interned at a company that does avionics/medical devices/financial software. Those industries do have strong regulations, like mandatory code reviews and traceability matrices. And that's great for what they do, but I'd hate to see the same standards applied to your Web 2.0 social bookmarking site.
Rebuttal here: http://enfranchisedmind.com/blog/2007/07/04/certification-pl...
The security certification is a wonderful idea! I think that would be a great place to start. (And end, perhaps.) The test for this could be entirely empirical. An applicant could be required to place $1000 in escrow, and implement a web application on the guild's servers. They would be required to add certain features. During the test, anyone would be welcome to try and hack the website. If anyone can prove that they are successful, they get the $1000. If the features all get implemented with no hacking, then the applicant gets their money back, minus the fee.
In other words: the market does do something, but someone could do even better.