Everybody keeps talking about web standards. Why is that?
I'll try to give a short answer first. A developer who designs and constructs a web document cannot know which computing environment his work will ultimately be displayed in. There are so many different flavors of computers, operating systems, browsers and their versions that it is unfeasible to write a version for each. This is where web standards come in. Standards define a uniform way to write web documents that can be understood on all devices. Standards allow developers to write just one version for all possible environments and ensure that no users are locked out.
By not supporting those standards (well enough) or creating proprietary ones certain corporations and developers create a fragmented web and force other developers to support only the lowest common denominator or exclusivly use a closed platform. This stifles innovation and freedom of choice.
Most of todays web standards evolve in an open process where everybody can participate. Of course the big players shape the overall direction of this process pretty much, but the important thing is that many competing corporations, not just one, are involved in crafting today's standards.
As a developer this means you stop wasting time fixing stuff for all the different platforms and are able use this time to actually build stuff, because it really works as expected. Instead of coding for the lowest common denominator you can now build rich internet applications: the so called web 2.0. Of course this is still not a reality entirely. Microsoft still pushes their proprietary technology and does a pretty bad job of complying with otherwise accepted standards. But the competition from the Open Source community has forced them in the right direction. Open source JavaScript libraries do the rest by translating between standards and proprietary quirks. That's what is powering this "golden age" of the web.
Complying with web standards also ensures that web documents can be interpreted or modified for use by disabled people, e.g. by using screen reading software. In many countries this is becoming mandatory and it simply can't be done without adhering to standards.