Remember the Linux Standard Base (LSB)?
The LSB was created to solve the challenges of multiple-distribution development and lower the overall costs of supporting the Linux platform. By reducing the differences between individual Linux distributions, the LSB greatly reduces the costs involved with porting applications to different distributions, and lowers the cost and effort involved in after-market support of those applications. The LSB enables ISVs to cost effectively target the Linux platform, reducing the ISVs' porting, support, and testing costs, while helping them address a global market for their applications.
One measure of the LSB's success is that we don't really hear much about it: instead, it beavers away in the background, minimising distribution-specific problems. Indeed, one of Microsoft's many FUD tactics against GNU/Linux was that there were just too many different versions. You don't see that argument these days, and that's largely thanks to LSB.
Moreover, LSB is still beavering away:
In another step towards general release, the first beta of Linux Standard Base (LSB) 4.0 was released today. LSB 4.0 will introduce a new application checker, a new shell script checker, and a new multi-version software development kit (SDK) that will enable developers to build applications to earlier LSB specifications without changing SDKs.
Which means that however good things are today, they will get better. So to answer my question: “LSB 4 for whom?”, whether we know it or not, it's for you, me and and everyone that uses GNU/Linux. Thanks, LSB.