Browsers usually support hot-keys too - try CTRL and - or + (for smaller and larger).
The fonts are all user-resizeable on our Web site and forums. Also, the appearance and size of all page elements has been checked on lots of different sized monitors and different browsers.
If the font size is too small on here by default it sounds like you could have an unsuitable windows resolution or system font size for your monitor. Alternative is that your browser isn't set to "normal"/"medium" font size (does the text on other sites look small?)
If you can't find the settings or require more help with this please send me a private message so I can get more detail.
Just like to point out that Firefox was the first Browser to obtain Accessibility approval by the US governing body on same by using Ctrl+ the minus or plus key (top row or number pad); IE was many months before being able to do the same. Firefox also was the first Browser to include support for web browsing speech provided web creators used the tools. I am writing this response in Konqueror, the default browser that comes with the KDE Desktop in Linux which also does the same thing with the Ctrl+ option and wheel of the mouse.