Usually people want to make the characters bigger so they can more easily read the print on a web page, but sometimes they want it smaller so they do not have to scroll from left to right.
Changing the size of the font (the size of the characters) can easily be done in Internet Explorer by pressing and holding the CTRL key and using the scroll wheel on the mouse. Scrolling up will increase the size and scrolling down will decrease the size.
This will work on most web pages. However on some web pages the developer specifically sets the size of the print font and you cannot change it.
This tip will also work on Adobe Acrobat documents. You can change their font size the same way.
This tip also works in Mozilla Firefox browsers and should work in other browsers.