While BlackBerry has not released the official numbers, analysts have been investigating the situation with their own channel checks.

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Michael Walkley wrote in a note to investors Monday, citing channel checks.

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Recent channel checks by Canaccord Genuity suggest sales have dramatically underperformed previous estimates, mainly because of supply constraints and limited support from carriers.

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Such channel-check information has become crucial to Apple traders, who have come to expect a weekly dose of information from channel checks about Apple's iPad and iPod businesses.

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Moran says his channel checks indicate that European online advertising has dropped from 20% year-over-year growth in the first half of 2011 to only 5% in the fourth quarter.

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As noted by StreetInsider, Hellawell wrote in a research report that his channel checks found that Baidu has lost 4-8 percentage points of search traffic since Qihoo entered the market on August 16.

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Channel checks in the U.K. and Canada, where the phones are already available, by Canaccord Genuity have forced them to revise their sales estimates for the new Z10s, which are now expected at only 300, 000 in the February quarter, down from a previous estimate of 1.75 million units.

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There are many reasons but the biggest two are the 36% gross margin guidance for the December quarter (after actuals of 40% in the September quarter and 47.4% in the March quarter) and multiple cuts by Street analysts of iPhone manufacturing plans based on channel checks (which may or not be accurate but there are enough of them to be a concern).

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The reciprocal arrangement means that French border police will make checks on the UK side of the Channel.

BBC: NEWS | UK | Politics | Immigration checks move to France