lucy24 - 2:47 am on Feb 25, 2013 (gmt 0)
The issue isn't font-family as such; it's font naming. Some very, very old versions of MSIE don't recognize it. And some not-quite-so-old versions of MSIE don't do Font Substitution, which is a far more serious problem.
You forgot font4, which will be either "serif" or "sans-serif". You need this because if the user doesn't have font3 installed, no two browsers use the same rules when they have to deploy Font Substitution. Opera for example seems to work in strict alphabetical order. (In my case this tends to mean AlphabetumDemo with the overlay because I keep forgetting to pay for it ;))
This kind of thing can be changed in browser prefs-- with the bizarre exception of Safari, in spite of being the font-friendliest browser around-- but very few users will have done this. Unless your target audience consists largely of people with the kind of linguistic background that means they will venture into the prefs.