Market research reports appear all too often, but some of them seem very different or contracting. It’s important you know what type of market share the new chart represents and what the numbers show. Some of them show market share based on last quarter alone, which is all about *new* sales market share. Others, like this one here, show how many subscribers in *total* the main platforms have, while others are simply being misleading by combining data that doesn’t make sense.

Also, some  are for US while others are for global market share, so that’s always good to recognize, too, because the US and global market shares are not always very similar, although it seems that the US and global ones for Android are pretty similar this time around, but still not identical.

So what we have here is a US market share statistic for the total number of subscribers for all these companies. So when they say Google has a 47% market share, almost double of their next competitor Apple, what they mean is that out of the almost 100 million smartphones currently being owned in US, 47 million of them are Android smartphones, 29 million are iPhones (not sure if iPod Touches are still included in these), 16 million are Blackberries, less than 5 million are Windows Mobile and WP7 phones (mostly Windows Mobile ones), and a little over 1 million are Nokia Symbian phones.

Once again, this is not about the last quarter’s sales, it’s about the total number of mobile devices in US. The only part that shows something about new sales in this table is that “change” column, which shows how many percentage points they all gained (or lost) during the September-December period.

So for now it looks like Android is still the fastest growing platform in US, and it also has a user base that is almost double that of Apple in US for smartphones. If nothing else, this should at least put developers on their toes, because many of them live in US and develop mainly for the iPhone, when Android is already on twice as many phones there.