Why do I get different search results in the online music store compared to RhythmBox?

view story

http://askubuntu.com – Why for instance when I search for Bob Dylan in the UbuntuOne music store in RhythmBox do I find his latest Album Tempest, yet it doesn't appear in the search results for the online store via the web? And if I buy from the RhythmBox store do I still get the offer of 6 months free streaming and 20gb of storage? (HowTos)