I found out about the text size thing a couple of years ago when I accidentally did it and couldn't work out what the hell had gone wrong with my computer as I couldn't work out how to put it back.
Otherwise, these shortcuts are indeed very useful and I use most of them daily now... Character map is the right choice for finding out what's available in your font set, I used to have a whole list of the foreign and scientific characters which I used regularly.

Anyone who regularly needs to write/edit scientific type text (and uses MS Office) should be sure to install MS Equation Editor or the more advanced Mathtype. The freely available Open Office also includes an equation editing program called
Math.
For Firefox users; middle-click a link and it will open it in a new tab. Middle-click a tab and it will close.