Shoutbox for your blog

A blog reader asked for visitor's registration. The only thing I can think about is either a Guestbook or a Shoutbox. I have written about Guestbook at Guestbook for your blog with an example at Natural Remedies. Clicking on the links in Guest will take your visitors away from your site (though you may chose to have the new site open in new window). If you want visitors to remain on your site,