that's what the non-tech guy on our team is for (among others things). constant user studies.
you have to be hitting the right crowd. asking advice from HN or random people only works if your site is meant to have universal appeal. HN in particular is a heavily skewed audience.
Once he's been on the team for a short time though, and if he's used the website a lot, then he's not going to provide the newcomers or non-technologists perspective. This is a situation in which increased knowledge of the user decreases their worth to the process.
It's very hard to pretend to yourself that you haven't seen something before and imagine your reaction - was that logo clear in its affordance?, etc..
you have to be hitting the right crowd. asking advice from HN or random people only works if your site is meant to have universal appeal. HN in particular is a heavily skewed audience.