Frank Atanassow writes:

Some people don't see it that way. They would say that the GPL is the _less_ restrictive license because it ensures that everybody benefits (equally) from everybody else's improvements. From that perspective, companies benefit also since they may use and improve the code, provided they "publish" it. Will they lose some potential revenue that way? Possibly.

As I understand it, the situation is worse than that. The mere existence of GPL code poses a threat to commercial software: if a programmer happens to read some GPL code and then goes on to use similar techniques in proprietary code, the owner of the proprietary code is in a legally difficult position. So not only is a programmer working on GPL code not generating any revenue, they are potentially threatening the intellectual property that the company already owns. Better all round for them just to avoid GPL code altogether. Cheers, Simon