At some point in the future, you’ll be able to create better webapps with a native feel and great handling of offline, cache, client hits (for much simpler responsive images), data streaming and fragmenting, progressive enhancement and gracefull fallback.
Currently lead by Google Chrome, closely followed by firefox, in consideration for IE and hopefully Safari will jump on it as well.
After seeing just the tip of the awesome iceberg of some of the capabilities that ServiceWorker brings, I was blowed away to a point that I just had to share it with you.