Web browsers are typically on rapid release cycles so they can get features out frequently. The Web is changing on a constant basis to help it become an effective application platform, which is cross-compatible with competing implementations. A common complaint is that the cycle is to yield high version numbers for marketing, to give a false sense of maturity, but I'd expect that frequent, breaking changes are kind-of necessary to synchronize features between implementations. If Google lands a feature a month after Mozilla publishes a new version, should they really wait two years for their next one? Granted, they probably knew about it pre-release, but you get the idea. Also, even if the theory is true, artificially high version numbers is one of the most benign things a company could do.
Some versions introduce some fairly interesting features, though. This one, Google Chrome 48, deprecates RC4 encryption for HTTPS, which forces web servers to use newer cyphers or they will fail to load.
Another major one, and probably more interesting for our audience, is the introduction of VP9 to WebRTC. This video codec is Google's open competitor to H.265. At similar quality settings, VP9 will use about half of the bandwidth (or storage) as VP8. WebRTC is mostly used for video conferencing, but it's really an open platform for webcam, microphone, audio, video, and raw, peer-to-peer data connections. There are even examples of it being used to synchronize objects in multiplayer video games, which has nothing to do with video or audio streaming. I'm not sure what is possible with this support, but it might even lead to web applications that can edit video.
Google Chrome 48 is available today. Also, as a related note, Firefox 44 should release next week with its own features, like experimental rendering of WebGL images offscreen and multi-threaded. The full changelog for Google Chrome 48 from Git is about 42 MB large and, ironically, tends to crash Firefox.