extremetech.com and geek.com
Extreme Tech's mobile site is totally unusable. They have a very crummy interface, instituted with javascript, that overrides the simple scrolling ability built into the browser and overlay it with a system that tries pseudo-pagination. If they would simply get rid of their attempt at a clever interface and just display their actual site, there wouldn't be a problem. If any Extreme Tech developers are reading this, please fix your mobile site.
The 2nd culprit, geek.com, crashes Mobile Safari. I'm on an iPhone 4. Because of whatever you are loading on your mobile site, it freezes the browser for upwards of a minute. Half the time the browser crashes before its done loading. Please, fix that too.
I actively avoid reading any of those sites, since I read HN from my phone about as often from a regular browser.
Another more generic complaint are to the people who use position:fixed on their sites to create headers and side navigation. Guess what, on mobile devices these don't scale. What ends up happening is that I need to zoom in to read your text, but then 3/4 of the screen is covered with your nav menu. Please, stop doing that.
Test your sites on mobile browsers. Its easy. Take the one in your pocket out and try your site. I'm not even advocating extensive dedicated testing. Just try it out like a normal user does and make sure it works most of the time. These are things that are so horrendously, obviously bad that I don't know how they ever got through any reasonable kind of QA.
Edited for excessive usage of caps. Sorry.