Forrester up tablet forecast: 1/3 of US online consumers to have a tablet by 2015

Forrester has revised its tablet sales estimates for 2011, claiming to have been "too conservative" with their forecast last year, and now predicting that 24.1m units will be sold in 2011. That's more than double the 10.3m estimate Forrester has put on 2010, and the research company expects Apple's iPad to hold the lion's share of sales through 2012. In fact, by 2015 Forrester expects 82 million US consumers – one-third of US online consumers – will be using a tablet.

Interestingly, part of Forrester's change in forecast is down to how often it believes owners will choose to upgrade their tablets. Originally, the idea was that it would be a similar timescale to that of a PC, but now the assumption is that it will be more in line with smartphone replacement cycles, as "lifestyle devices."

We spoke to analyst Ben Bajarin, who tells us that he believes Forrester's predictions for 2011 are still far too low. He's forecasting 2011 US sales of 50-52 million units, as iPad rivals such as the BlackBerry PlayBook and various Android slates reach the market.