[jraph]

Free software licenses and open source licenses are almost the same set, and the difference between the two is not copyleft: the GPL is OSI-approved. The difference is in the spirit, focus, philosophy: free software is concerned about user rights.

And if you care about user rights, use a copyleft license to prevent someone from building a proprietary derivative, even if you are not turning it into your day job. Especially if you are not turning it into your day job, a copyfree license is more likely to atract corporate.

[bruce511]

Exactly. If you care about "who" uses the code then Free software certainly helps to limit that.

If all you want is to offer "here's some code, knock yourself out" then a license like MIT and BSD is generally more useful to more people.