However, I believe that the jobs tab is a significant competitive advantage for the YC portfolio companies.

If you contribute to the community you can expect the community to give back.

There's a trade off.

Contractors cost more per unit time than do employees (in the short term), and are usually looking for the next gig. At a startup, we don't have tons of free cash, but we do have tons of potential. We'd rather reward someone with a promise of sharing in our success (which we have) than with twice as much cash (which we don't have).

As far as working on site versus off site: again, I have no moral objection to this, and I've done it myself. However, I'm not just hiring engineers to produce lines of code: I'm hiring them for their wide-ranging intelligence, their ability to contribute to the ideas bouncing around the office, and their ability to tell me when my ideas are full of shit. All of this takes place much more easily in an office. Finally, while most people who work remotely are professional about it, I have noticed that it becomes easier for someone to disengage, grow tired or frustrated, and mentally "check out"...and it's harder for me to detect this, and take appropriate action (a word of encouragement, an announcement that we're all bagging work for an hour to go get a burrito on the company's dime, or whatever else).

As much as I like the IDEA of remote work, and easily compartmentalized tasks, I have come to believe that humans have evolved to be highly social, and to work best when they are immersed in a social environment.

I note that Joel Spolsky has company lunches every day, and considers this important.

Here's another thing that's really bothered me as a job seeker.

Most employers will say something like you did "I'm not just hiring engineers to produce lines of code: I'm hiring them for their wide-ranging intelligence.." but then proceed to ask me excruciatingly detailed trivia during the interview, or require someone have X years of experience in some technology. If you're hiring for intelligence, should it really matter if the employee hasn't use technology X before? He should be able to learn quickly.

Perhaps your case is different though. RoR is more like a movement than just a technology so maybe it's a good indicator of sucess for a candidate to have already used it.

From my experience in startups, most of them care just as much about your 2 cents as about your LOC.

Because startups are much more malleable and prone to change their direction, strategy, market & product every input matters and sometimes you can recoup your entire hiring cost for an engineer from a single sentence he says offhand in some discussion.