Rollerblade is merely a brand name. One which most IN-LINE SKATERS I know do not wear. It is IN-LINE SKATING. Learn it. There will be a test. The big player now is K2. I personally wear Oxygen. Great skates that I got cheap because they are going out of business (too bad). California Pro went out of business, but they sucked.
Rollerblade still is quite active. But the activity is IN-LINE SKATING.
(shrug I need something to pad my post count so I might as well post here)
I usually call it rollerblading. Even if it isn’t the rollerblade brand name. It’s just easier to say. Or just “rollerskating”/“skating,” but that is more associated with (“laaaame”) non-inline skates.