Amazon Buys Goodreads has purchased popular “social cataloging” site Goodreads for an undisclosed sum. Goodreads was founded in 2007 and has about 16 million active members, who use the site to catalog books they own, have read, or want to read; to review books; and to socialize online with other readers.

With this acquisition, Amazon now has a stake in all the major social cataloging sites, with its own site Shelfari and a minority ownership share of LibraryThing.

Reactions to the announcement have been mixed, with some Goodreads users excited by the possibilities of the partnership, and many others  worried about potential changes to the site.

For more, see the announcement of the sale at Goodreads (and the hundreds of comments from users).