Provide high-level project background & benefits

[anthumchris]

It would be great to have a high-level blog post or Background section that provides an introduction on why Polymer started, it's mission, how it benefits the developer community, etc. This could help newcomers or those who are researching and comparing libraries/frameworks to use. The list of blog articles currently provides excellent technical information, tutorials, and release info. Would be great to see more high-level to help us with architecture, planning of a new app, or migration from other technologies.

For example, the Use The Platform concept is great yet not immediately visible or explained on the website.