The font list is provided by Yahoo Mail, not by Firefox. Yahoo probably offers a limited selection of fonts because the fonts won't work unless they are also installed on all the recipients' computers.

Dear mbrubeck, Many thanks for your prompt answer and the clarification provided therein. But my situation is that I have only one Notebook computer (HP Pavilion dv6704TU) directly connected to the Internet. Then, where is the question of "all my computers" being connected to the Internet? I would be grateful, if you could spare a little bit more of your time to make me understand what I should do. Regards. - - arasan77