Amazon.com’s expansion of its Amazon Kindle websites, a social network that connects users of the online retailer’s e-book readers, has drawn mixed reviews, including some criticism for what privacy advocates say is a “creepy” lifting of users’ list of friends and acquaintances from Facebook and Twitter.

The Kindle website had struggled to gain traction among socially networked readers since being launched in February. That changed when Amazon connected the site to Twitter and Facebook accounts. While users’ preferences are set to private by default, any user who opts to share notes and highlights from books they are reading via Facebook and Twitter will also automatically start following anyone in their contact lists who has opted to do the same.

Amazon, in other words, is taking users’ permission to broadcast their reads to friends via Facebook and Twitter, and using it for a completely different purpose: building out their friend networks on Amazon’s own site.

It’s an embarassing misstep for a company that was once actually a pioneer in social networking. Amazon.com acquired a startup called PlanetAll in 1998, securing a key patent on social networks. While it shut PlanetAll’s website down in 2000, many of the site’s early social features, like birthday reminders and lists of friends, stem from that acquisition.

On the kindle site, the all-or-nothing approach is what’s unsettling to some users. While Amazon reportedly made no announcement about the change, it did offer a note of explanation on its Web site: “As a convenience, whenever a Facebook friend starts to use kindle.amazon.com, or you become friends on Facebook with someone who already uses kindle.amazon.com, we’ll make sure that you follow them here too.”

Contrast that to the approach of Foursquare or Yelp. Their mobile apps, when linked to Facebook accounts, send notifications to users that a Facebook friend has joined the service, but don’t automatically sign them up as friends.

Barnes & Noble, which competes with Amazon in online book retailing and sells the competing Nook e-reader, has explicitly stated it would not auto-add friends to its Nook Friends social network.

In a report on the move, Wired’s Tim Carmody repeatedly described Amazon’s move as “creepy.”

Others had a rather ho-hum take on the retailer’s renewed social push.

In response to a ReadWriteWeb review of the service with the headline “Amazon Brings Social Reading To Kindle -- But Will You Use It?”, blogger Keith R. Harden tweeted a one-word answer: “Doubtful.”

Photo by M.J.S.