7 tech revolutions that flopped

Amazon (AMZN) unveiled the Kindle e-reader in 2007 to acclaim and amazement.

It wasn't the first e-reader, but it was the first successful one. The Kindle had a battery that lasted weeks and gave people the ability to carry 700-page books in their bags without feeling like they were lugging a ton of bricks.

Competitors to the Kindle quickly cropped up, including the Barnes & Noble (BKS) Nook and the Sony (SNE) Kobo. But, like it did with the netbook, the iPad also has begun to kill off the e-reader. About a third of e-book readers say they use an iPad to read, and 22% use their smartphones, according to a study published last week by Forrester Research.

Sales of e-readers spiked to more than 13 million in 2011. This year, e-reader makers are on pace to sell just over 4 million, and Forrester predicts just 2 million will be sold in 2017.