Amazon.com (AMZN) has entered the Twitter-sphere with new program, drawing a mix of criticism and praise among users.

According to TechCrunch, Amazon.com has launched a new feature for Amazon Associates entitled "Share on Twitter." The program allows associates to tweet about products sold at Amazon, generating quick and easy links back to a page on the bookseller's site. In an email to associates, the company wrote: "When Twitter users click on the link in your post and make a qualifying sale, you'll earn referral fees."

Many readers are worried that these referrals might harm the integrity of Twitter. ReadWriteWeb had these thoughts: "Soon they'll start promoting a great book they just read, a DVD they liked, or one of a million other things pulled out of Amazon's vast inventory. None of it will sound out of place given the types of informal conversations that take place on Twitter every day. You won't even know that they're advertising to you until you click through on the link and find yourself on an Amazon.com webpage--and even then, you may not be sure." (Via Jose Afonso Furtado)