(Correction in progress. I wrongly announced the release of the second discussion draft but the final version was actually released.)
FSF have just published the 2nd draft of the GNU Affero GPL. The GNU Affero GPL will be a modified version of GPLv3. The difference, very roughly, is that it includes a requirement that if the software is used on a public server, users must be able to get the source code.
This issue was discussed a lot during the GPLv3 drafting process. Some software developers thought that this requirement should be in GPLv3. However, the majority of software developers who commented strongly disagreed.
The topic was controversial because there is a privacy issue. All versions of the GPL allow people to use modified version of the software privately without being obliged to make their modified source code available to anyone. When people put software on a public server, the question is less clear: is that private use or public use? This was called the "software as a service" issue, or "SaaS".
FSF decided that developer unhappiness was enough of a reason not to add this requirement to the standard GPLv3. If developers didn’t like GPLv3, they wouldn’t use it, and if people don’t use it, it can’t do it’s job of protecting software freedom for computer users. Instead, FSF will publish a separate version, called the GNU Affero GPL, which does include this requirement and each project can choose if they want a GPLv3 with that requirement or without.
So, that’s the background. The second draft is online and comments are being accepted via the same system used for GPLv3. If you might have something to say, go take a look!