Neko is a self-hosted shared browser, which was built in response to a product called Rabb.it shutting down. Rabb.it had ~4 million MAUs and raised a series B before shutting down due to investors pulling out last-minute during their series C fundraising.
Rabb.it was focused on watch parties. There are a few reasons why shared browsing is more appealing than video sync and screenshare for this use case:
1. Screenshare requires good uplink—some people only have good download speeds
2. Some people are uncomfortable with sharing their screen, nobody likes being judged for their bookmark choices
3. Nobody acts as a "host", control can be passed around to anyone and people can leave whenever they want
In other words, you get the content variety of screenshare, but with the convenience of video sync.
And now for a shameless plug :)
Hyperbeam (formally Tutturu.tv) is a site I built in 2019 for my capstone project at the University of Waterloo. I built it because I wanted an easier way to watch anime with my friends, and decided to build something similar to Rabb.it. It's hosted and free! https://hyperbeam.com