Best thing I like about Mozilla stuff, is the fact that it's all open-source. Anyone can modify the programs to their liking, provided they know what they are doing.
There are pages and pages of add-ons and other bits and pieces on the Mozilla website, that ordinary people have written.
One good aspect of this open-source idea, is that any bugs that are found in a given application are fixed pretty promptly and notified on the Mozilla website.
