It carry the same meaning as "awesome" but B2UTYs (b2st's fans) changed the "some" to "soom" to celebrate the releasing of B2st's 3rd Mini Album Mastermind.. and their title track "Soom"..
Please give B2st lots of love~^^!
A: "Hey, guess what? I just bought the tickets to the concert!"
B: "OMG! That's AWESOOM!!"