Keep your hands off my font size
There are many things that puzzle me about common web design. One of the biggest thing is this: why do so many sites reduce the font size of their main content? This is the single largest readability problem that I run into on the web. (For some reason this seems to be especially prevalent on blogs.)
I see it over and over again, in CSS like 'font-size: small', 'font-size: 80%', 'font: normal 76%/140%', or even 'font-size: 12px'. (At least CSS 'px' units aren't absolute pixels, although a lot of people think they are; see here. Please note that if they were, 12 pixels might be absurdly tiny on a high resolution display.)
I'm going to be blunt: resizing your main content text smaller is plain arrogance. The user and the vendor have set the browser up at a text size that they feel is nicely readable but not too large, and you think you know better than they do? Wrong. Even if you're an experienced typography and layout designer, the web just doesn't work that way.
At best it looks good for you and some of your friends. From lots of personal experience, I can assure you that for a lot of other people it looks like ass. Often the Mozilla View/Use Style/None menu option is the only thing that makes a distressing number of web sites vaguely readable for me.
Of course doing this destroys all that nice CSS design you did. Hopefully your content is attractive enough to keep my eyeballs. (If you don't want my sort of eyeballs in the first place, you can save both our time; just put up a web page that says 'you must have browser X on operating system Y to view this site'.)
Please save setting the font size smaller for things that are, you know, not as important as your main content. At least I hope that your main content is the most important thing on the web page.
(The other reason that this puzzles me is that I don't understand the psychology involved, because for me smaller font size means 'less important'. People marking much or all of their page as less important boggles me.)
(After thinking about it, I have decided against including links to representative blogs. If you think I'm talking about you, I probably am.)