A series of articles by Bram Stein on typography, performance and modern day best-practices for using fonts. I particularly like what Bram has to say on overusing web fonts:
Another recent trend is using web fonts where they’re not appropriate. Don’t use web fonts if you don’t need them. They’re not the right answer for everything. If you find yourself wrapping each letter or word in a
spanelement in order to style them — stop. Use SVG.
Most of the times when you’re wrapping words and characters in
spanelements you are actually attempting to do lettering in HTML and CSS. There is a fine line between type and lettering, and web browsers are not great at the latter. SVG on the other hand is a great fit for lettering. It’ll give you absolute control over kerning, tracking, position, gradients, masking, and colour. As an added bonus, the resulting SVG file size will be smaller than loading several fonts.
Anselm Hannemann also has a take on webfont loading best practices.