NEW YORK — When Google unveiled plans to fund 100 new channels of original programming on YouTube, many expected a transformation of television. Just as a handful of networks begat a few hundred cable channels, YouTube would foster the birth of thousands of online channels.

A year later, such a sea change isn’t palpable — and probably shouldn’t be expected so soon — but YouTube’s platform of programming is gradually taking shape, building into an global ecosystem in which the tools to produce a mini TV station are anyone’s.