[adrusi]

You have to make your site accessible to search engines, so as long as you're not doing something weird like using javascript for styling and layout, just treating users who have disabled javascript as search engines should work just fine.

[bsimpson]

Google has been working pretty aggressively at learning to crawl JS-framework-powered apps lately. I'd still play it safe and serve up HTML when possible, but JS isn't the SEO black hole it once was.