This project is from Zero to Mastery: Jacascript Web Projects: 20 Projects to Build Your Portfolio. This is project 10 / 20.
You can view a live version of the project here
You can view the full list of project from this course here.
I really don't know how practical a bookmarking website is. HOWEVER. I can see this functionality being useful as a feature within a website. The website Board Game Geek uses this feature. There is a "Quickbar" at the top where you can add your own custom links (within BGG), to different pages. This makes it easy to go to different parts of the website. I actually use this feature pretty extensively on there.