Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, Contentious.com, explores how people communicate in the online age.
(CNN) -- This holiday season, many people received e-book readers as gifts -- but what about the books?
It has been surprisingly difficult to give someone an e-book as a gift. You could buy them a gift card for the e-book service of their choice, and maybe suggest which book to purchase, but you couldn't actually purchase it for them.
In November, Amazon changed that. You can now buy a Kindle book as a gift. Recently I tested this by purchasing a holiday gift for a friend. She reported that obtaining my gift was easy -- she got an e-mail notification of the gift, clicked a link in the e-mail, clicked a link on the Amazon site to accept the gift, and then was able to download the book to her Kindle. This process also works for people who use the free Kindle smartphone or tablet apps, rather than the Kindle device.
However if someone you know uses one of the other popular brand-name e-readers, they're probably out of luck for direct e-book gifting. So far, you cannot give a Barnes & Noble NookBook directly as a gift. Nor can you give an iBook, or a Sony e-book.
You can, of course, buy or obtain e-books in other formats -- there are many: plain text, HTML, PDF, MobiPocket, ePub, and more. But you'd need to check first whether your recipient would be able to use these book formats, and that would probably ruin the surprise.
As a Kindle user who has many friends who also use the Kindle, I'm glad that Amazon finally began offering this option. Obviously it can be done, and the experiences can be user-friendly for the buyer and recipient.
But I'm surprised Apple, Barnes & Noble and Sony haven't followed Amazon's lead on this. They're just leaving money on the table -- and in the current tight economy, what retailer can afford to do that?
The opinions expressed in this commentary are solely those of Amy Gahran.