With all the buzz about the iPad and the many other tablet devices that are hitting the marketplace, you might think that single-use devices like ereaders are poised to have short lifespans. Already Cisco killed the highly popular Flip video camera claiming single-use devices are no longer relevant in a world where smartphones and tablets can do the same thing and so much more. (On a personal note, I'm still mourning the demise of the Flip). However, such thinking might not be entirely appropriate -- at least, not yet.According to new data from eMarketer, ereader use continues to grow -- and fast! This year, ereader sales jumped by 60%.Check out the chart below which shows ereader growth since 2009 and projected through 2012. As the chart shows, by 2012, 12% of the U.S. adult population will have an ereader such as a Kindle, Sony Reader, or Nook. That's up from 8.7% in 2011 and a huge jump from the 1.9% in 2009!

The most interesting part of this story, however, isn't the number of ereaders people have purchased but rather, ereader penetration. As eMarketer notes, research from Nielsen shows as many as one-third of ereader owners share their devices with at least one other person. That means far more than the predicted 12% of the U.S. adult population who own an ereader are actually using ereaders.It seems that immediately ruling out the importance of single-use devices will lead to missed opportunities to connect with large audiences. For publishers, marketers, brands, and businesses, that could be a big mistake, particularly since Amazon has launched its low-cost, ad-supported Kindle that has quickly become its top selling ereader device.What do you think? Are single-use devices still important? Leave a comment and share your thoughts.