Google Reader has introduced new comments features to its online and iPhone service.

The service, that lets users read and share articles, blogs and videos already offers functionality that allows items to be shared with a note, but this has now been extended to "conversations" about the items.

In a blog post Google says: "We're excited to announce that starting today, your friends will be able to reply to shared items with comments, allowing you to have conversations with your friends right inside Reader".

Comments can only be seen by friends of the person who originally shared the item so discussions are private.

Google has more information about the new features on its Reader blog.