well they are both folk metal bands and so they will tend to use the same style of music, but alestorm is more pirate orientated while moon sorrow is more surrounded by folklore
i think you mean Alestorm sounds like Moonsorrow, considering the band Moonsorrow and this song, predate Alestorm's formation. In addition Alestorm have listed Moonsorrow as an influence for their formation and music. Although, Finntroll is more up their alley in style and ridiculousness (also listed as an influence by them).
