"But the fact that there are 73 licenses is a problem.
Many of those licenses are incompatible with each other. To
understand the legal implications of mixing software under two of
those licenses together in the same program, you'd have to learn
5256 different combinations!
"And the worst thing about this is, it's my fault! Well,
partially. When I wrote the rules for Open Source licensing in
1997, as a policy document of the Debian project, not many people
took what we then called "Free Software" seriously, and it was
unthinkable that 73 different licenses that complied with my Open
Source Definition would ever be written.
"Fortunately, you don't have to deal with many of those 73
licenses. When you need to distribute or modify software that is
under one of them, you'll need to understand that one. And folks
who are just users get off easy: you don't really need to read an
Open Source license just to use the software, because the rules I
wrote require that the license give you the right to use Open
Source software for any purpose."