@tubularglue
The AddThis Javascript isn't for advertising, it adds the Share icons to the top of the articles, like share to Google Buzz, Twitter like on Facebook. So AdBlock add-on doesn't 'block' it. I did add it and its nice. All those other 'ads' are getting called from other services so blocking 'em eliminates a bunch of http requests to load a page on CN and definitely speeds things up. Thanks for the tip!
The AddThis javascript still seems to slow things down, but it is intermittent, sometimes it loads really fast, other times its pretty slow. My power cuts out at least 1x per day. When that happens FF acts like it crashed, so I lose whatever was 'new' in my cache. I think that might be it. When I have the AddThis JS and images in cache its fast, when I have to fetch it anew I can experience some lag?