Nielsen's data covers the period June to November 2010 and compares the three smartphone OS leaders, Apple iOS, Rim Blackberry and Android. It notes that all three are benefitting from a strong demand for smartphones over feature phones. In November 45% of  "recent acquirers" (those who had purchased a phone in the past 6 months) opted for a smartphone.

It is the trend in the relative popularity of the three leading platforms that is remarkable. Over the full six months Android has increased its share from 27% to 41% while Blackberry has declined from 35% to 19%. After an initial jump from 21% to 26% in June July Apple has seen little further change and ended the period with a 27% share.

However, when all smartphone users are taken into account and we look at the graph for overall consumer market share, Android OS (26%) is still behind Apple iOS (29%).

According to Neisen,

RIM Blackberry's position is less clear: Its share (26.1%) puts it within the margin of error of both Apple iOS and Android. In other words, RIM remains statistically tied with both Apple for first and Android for third.

While Neilsen refers to "Apple's clear lead over Android" an alternative reading of this graph is that if the trend continues Android will soon tie with Apple and then overtake it to become the dominant Smartphone OS.

Further reading

Mobile platforms of the world!

Android 2.3 and the Nexus S development phone