As I was trying to get myself up-to-date with the new Shootmania blocks, I noticed a new kind of block, one which looks like a purple portal. However, as far as I can tell, it only acts to prevent players from jumping in a certain direction. What do these blocks actually do, though? I'm certain I'm missing some rather vital info...

It's a teleporter. Stand on a flat one, aim to a standing one and press jump to teleport to the standing portal you're aiming at.

You can also hold jump/"action"/stamina and aim constantly to more quickly teleport to the target teleport.