Sentence:  Soundcheck for the band, today, takes place at the Hollywood Bowl in Los Angeles. It is late afternoon and while the arena's 17,000 outdoor seats are still empty the four members of Mumford & Sons – prospering British folk band, in the middle of a long tour of Australia, the US and the UK, their newly released album Babel a <WSD>smash</WSD> on all fronts – wander to centre stage. 
Meaning of the word marked with <WSD> tags:  Something very successful.