I wanted to start a separate thread about the issue of LaTeX appearing bold, although Kannappan raised it in his recent question, because it appears to have expanded in scope, and because that thread currently has an accepted answer dealing with the other part of the question.
Here is a screenshot I took today (I'm using Chrome 18.0.1025.142 m on Windows 7 64-bit). This is the page where I took it so you can examine whether you have the same effect or not. You can click on image to go to a slightly bigger version.
The math that occurs in the comments, and now also in the sidebar, is significantly bolder than usual (the question and answers themselves seem unaffected). I've looked at many other pages and they all have a similar effect.