well the biggest problem of the term "free software" may be its ambiguity, and M$ did said IE is "free software"
but the "open source" also has some problems:
1) the average users don't know what "source" is
2) MOST of the people just mean "source is available" when they are saying "open source"... but that's WRONG; such things like game modding SDKs are NOT "open source" as using parts of their codes in our software is illegal. Also some hackers like to write such license terms like "This software can be only used for non-commercial purposes" for their "open source" software but that is one of the restrictions which made the software non-free or not "open source"
3) plus all the comments which Free Software Foundation has made at:
http://www.gnu.org/philosophy/free-s...r-freedom.html
the Mozilla source code is too huge for me to learn
but if some hacker (not cracker!) discovered a security hole in it he is likely to report it or publish a fixed version. and for non-free ("closed source" - gotta make this comment to avoid ambiguity) MSIE or Opera only the author is able to do so... so if they don't fix it you'll have to bear with those bugs... in other word, you are *completely* at the mercy of the authors...