There is a very important philosophical reason to use the GPL. My next bit may sound too self important or the like, but philosophy is like that.

Here is a claim: Human progress is made up of mechanisms in society which make people co-operate more when they short term interest is to co-operate less. Usually this also involves serving some of the other self-interests that these people have (in the end people always serve their own self interest).

Examples:
– marriage: the father (usually) would leave the mother after childbirth. In early societies we would be huddled in clans and so the clan would, communaly, take care of the infant. But today there are no communities like that so the marriage idea was born in order for the mothers and childs right to be protected. Ofcourse it gives some guarantees to the father too. But in essense the marriage concept is about trying to force fathers to co-operate with their families.

– law and police: forcing all people to co-operate (sometimes against their will!).

– taxes: no one likes paying them but there would be no state without them.

– the UN: trying, by force of groups of states, to force states into co-operation.

– capitalism – trying to encourage people to serve their own ends not by killing other people but rather by selling things to them. This selling of products usually forces one who wants to go down that road to form a company which is a bunch of people co-operating. With no incentive for profit this would not have happened.

And finally the GPL. The GPL forces (again, not in all situations) co-operation amongst people making software. They may not like it at times (as they may not like taxes) but in the long run their interests are served better by the GPL than the BSD license.

So there is a very important philosophical reason to prefer the GPL

Mark

PS. The different between co-operating against my will opposed to co-operating out of consent is not as important as some people would like to believe (if I park my car in the right spot because I payed a fine previously and would like to avoid a further fine am I doing it out of my “free will” or out of “forcing” by the government ? Probably both. But it does not really matter which as long as large groups of people co-operate…).

Vitaly [I was on you mysql performance course last year]

i agree with you

it is obviously not true what you are saying, and what I pointed out earlier there is no license will protect you from an in-house usage by any company. how can you prove that somebody is using your code if there is no public visible sign of it?

Also, ask yourself if you would rather have someone redo the work you did, possibly less well, than use your work to build on when they are not going to contribute back. For myself, the answer is that I’d rather have people spend time on new code and re-use what has been done once well enough.