2000s in the music industry Inc.), who surpassed Wal-Mart to become the US’s largest music retailer in April 2008. Sector leaders include: Many hundreds more stores operate worldwide, often prominent only in particular countries or specialist genres. A third kind of operator never retails directly to the public, instead offering branded whitelabel stores and portals for organisations including bricks-and-mortar music stores, mobile telephony operators and ISPs. Some services which initially only offered streaming of tracks now also offer a-la-carte downloads, either through third parties (e.g. Spotify) or fully integrated (Deezer, Juno Digital, Rhapsody etc.). In 2009 "Rolling Stone" reported a price war between iTunes and
Tidal prism not as great as in shallower estuaries creating a smaller tidal prism and a longer residence time. The size of an inlet or estuary is determined, according to O’Brien by tidal prism. Tidal prism magnitude can be calculated by multiplying the area of the estuary by the tidal range of that estuary. During spring or fall tides, when sea level is relatively high and floods backbarrier areas that are normally above tidal inundation, the cross sectional area at the entrance of the estuary increases as tidal prism increases. Since tidal prism is largely a function of area of open water