YouTube is the dominant online video service, and feeds data it generates about your activity into and from your profile.
Other services are competing with YouTube, however, and some respect your privacy far more.
Vimeo is the next most dominant video service, which is unfortunate, as it also exploits user data and shares this data with third-parties, including Google.
PeerTube is a federated video hosting service. This is much better for user privacy, and enables users to host their own instance, with their own videos, and knits together a network of peer-to-peer broadcasts, so when you use it, you actually contribute to its bandwidth!
DTube is a new, decentralized video streaming service built on Steemit and IPFS, which is far more privacy protecting than centralized video streaming services.