Lmfao why does this have so many downvotes when other blading threads on here get super upvoted.
anyway yeah you say roller skating, there's actually a difference between aggressive roller skating and aggressive inline.
roller skating is the one with four wheels in a square like a skateboard. You can put a grind block between the trucks and do grinds on that.
inline skating aka rollerblading is the one with four wheels in a line (hence the name inline), and some inline frames have a groove to do grinds with. You can also do grinds using the soulplates, which are the flat bottoms of the boots themselves.
A lot of people who are experienced with park skiing pick up blading really fast. Doing a basic frontside on a rail/box is gonna come really quick if you're used to doing it on skis. The one thing you have to get used to is transition/quarterpipes etc. as you have way less support underfoot compared to a ski.