No, it's linear complexity.

No, rev was in previous versions of HTML, but was apparently dropped in HTML 5, probably because people didn't understand the different between rev and rel.

rel="canonical" and rev="canonical" are different things

This is known as hashcash. One big reason that it doesn't work on the web is that, currently, users will be stuck with some slow JavaScript version of the algorithm, while a sufficiently determined spammer can use a fast C version, and end up with much less work required to post. So it's nearly impossible to set a cost that is cheap enough for valid visitors, that will be a sufficient deterrent against spammers.

SILC, however, fails the "log everything" requirement, by design.

Good point, but the other side to it is that if we go back to the idea that if you don't like it you can fix it. Whereas the coding can be a heavy time investment, hiring developers can be a heavy financial investment, perhaps costing even more than buying a proprietary program to do the same thing.

Agreed, as long as there is a proprietary program that does what you want it to (or close enough to what you want). ;)

With the industry that I work in, the proprietary solution is very expensive, and the FOSS solution does 90% of what people want, and custom development is fairly easy.

Modifying OpenOffice.org or Cinelerra is probably a much harder task.

This assumes that you have to be the one who does the coding.

I work for a company that does custom development for a certain piece of FOSS. We get paid by people who can't do the modifications on their own, and we happen to be making good money doing it. With FOSS, you can contract out the work to anyone who has the time and ability to make the changes. With proprietary software, you need to hope that the company will listen to your requests.