Although I use Google Reader sporadically, for some of my favorite blogs, I sometimes can't break the habit of going to the actual blog site.
But more and more, these blogs are filling up with images, inline YouTube players, a ton of ads, crap like sphere and digg iframes, etc.
The fact is, over time, they accumulate a bunch of crap that slows them down.
How slow are they? I installed Firebug, and YSlow to check load times:
Leading the list is Fred Wilson's blog famously full o' crap (not referring to his writing, of course). Note that the VCs tend to have slow blogs. That tends to happen when you stick a bunch of ads on your blog. And what, do the VCs really need the adsense money?
Actually, the technorati tend to be early adopters of blog craplets, and then never take them off (or in Wilson's case, replace them with even heavier / slower crap).
Perhaps the subtle takeaway is the inverse correlation between speed and number of readers. At least in the tech world, the slower you are, the more readers you'll have.