Or, know how to install adblockers :)

Do people with adblockers count as an impression?

Typically not. They don't initialize the scripts that are required to track and log the impression.

It's pretty well known that techies don't click on ads, but they're only a smaller segment of the internet population.

..until your site has them as your core audience..

I was implying that ads isn't a good way to monetize that audience. Sponsored content or affiliate networks is better.

I was under the impression that most modern blockers (uBlock etc) simply block that request from the site to the adserver, so no they wouldn't count as an impression.