Stickies are designed to be “super-bookmarks”. When you right click on a tab and choose Save to Stickies, the URL will be attached to the Left Navbar and as an icon (if the URL has a favicon).
The purpose of Stickies is to keep the most important URLs associated with the Workspace easily to hand. Typically these are the sites you go to most often. Clicking on the Sticky’s icon will open the URL in a new browser tab.
If your Workspace is shared as a Team, the Stickies are shared too.
You can remove a Sticky by right clicking on it and selecting Remove.