Seeing a dramatic increase in iPad sales after conducting additional consumer surveys, supply-side research, and an SMB and enterprise survey, as well as briefing many companies that are to release tablets at CES, Forrester realized that they were too conservative of the previous prediction released last June 2010.

Yesterday, the research firm published a revised US consumer tablet forecast. The prediction contains an estimate of 10.3 million tablets sold last 2010 and 24.1 million units to be sold in 2011, a figure double from the previous year. Also, despite many companies set to release their tablets at CES, the iPad will still get the biggest chunk of share for 2011, and throughout the following year. Another tablet player, Samsung’s Galaxy tab, is also making its way to the market, but not quite certain if it can catch up with Android and iPad. Also, here’s an earlier report from our news editor Kristen Nicole, which pretty much aligned with that of Forrester’s before they updated their forecast.  How quickly things can change in the consumer electronics market.

Another major factor that caused Forrester to revise their prediction is the so-called replacement rate. Tablets are viewed as “lifestyle devices,” and as such are closer to MP3 players or iPhone than PCs. It is a device that consumers will consider upgrading faster than they would a PC. To put it simply, those who purchased first-gen iPads are likely to buy an iPad 2 that is to be released this year.

In 2015, consumers in the US are estimated to be about 82 million, one-third of which will be tablet-owners, however, not all of these tablets are iPads. Android, Playbook and Windows-based tablets, as well as tablets on HP and Nokia platforms might be behind Apple but that doesn’t mean they will slack too badly. With a market this big, one player cannot possibly cover everything, and competing manufacturers are always anxious to develop Apple alternatives.