The PrintFriendly plug-in generates printer-friendly views of the page
it is inserted in. The printer-friendly view is only generated if
the user selects it; the regular template is used by default.
When you place the PrintFriendly tool on a page, you have a few options
for how the "printer-friendly version" link is formatted.
The printer-friendly view is generated by replacing the regular page
template with a very plain template that shows only the page
body. That means that the printer-friendly view only applies to
the page body; other content will be excluded.
Bugs
If you have any fancy CSS tricks embedded in the page, the
printer-friendly view may not reproduce them properly, because its
simplified layout may not be able to handle your CSS.