Interestingly, the original (few) versions of the GPL did not really imagine a web services world - and so there's been a major loophole for the last many years. If any GPL'ed software is being used on servers, the bits are never "shipped" to customers. Therefore, Internet companies are free to take any GPL software, modify and change it - derive SIGNIFICANT benefit from it - and NOT release the source code. Even if the functionality is identical to what you might provide with desktop software bits, you're free to keep the code "closed", so long as you don't ship the actual executable compiled from that code to the end user's desktop.
It sounds simple, but in practice this is somewhat subtle.
You can take the functionality of ANY such software, "remote" the functionality (i.e. have it run on a server instead of the local machine), and completely circumvent the GPL. Doesn't matter how much value that software created for your Internet business, or how much your improvements might help others. Taking an IP and business view, that means you can leverage the benefits of OSS (free labor, community review, improvements, etc.) without paying the capitalism "tax" that it might impose - so long as you don't care about installing desktop software.
No wonder Microsoft hates it :P
Part of the rationale for the new version is to attempt and rectify this loophole. I'm a little worried about the "... and then some" provisions they're including - very wierd some of the requirements version 3 includes (about source distribution requirements among other things). It'll be interesting to see which major GPL open source projects (Linux, Apache, etc.) switch to the GPL v3, and what implications this has for the Web and its standards.
If any of the major OSS web infrastructure projects does adopt it, I predict we'll see some MAJOR fracturing over time, as commercial companies fork from the previous GPL'ed versions. If nothing else, we would get a chance to see who thinks with their wallet - but pretends they don't.
Linus Torvalds, of Linux fame, does not like GPL 3, at least in the case of the Linux kernel itself (though I suspect this has more to do with the odd requirements than the attempt to close the web services loophole).
[To be concluded in part 3...]