Blogging is definitely not a single-way interaction property in Web 2.0. In fact, massive interactions between author and visitors are the funs of a blog. Visitors are allowed to leave a comment, contact author, vote for a post, or even chat in provided shoutbox.
Chat box/shoutbox is a trend for visitors to exchange an opinion with other visitors in public. It is a new interaction possibility for visitors to a website. With a Chat box/shoutbox, site visitors develop a durable personal relationship with your homepage.
In SEO term, it reduces your bounce rates, creates more chances for visitors to browse through other contents, more regular visitors and of course, more impressions.
Here’s 18 free and customizable chat box that able to optimize communication platform for you website. Detail next!
- Blom
- GagaLive
- CBox
- ShoutMix
- Shout-Box
- YellBox
- FreeShoutBox
- MyShoutBox
- ShoutBoxPro
- YShout
- PHP Shoutbox
- wTag
- V3Chat
- Free-ShoutBox
- Naruto Shoutbox
- Flash ShoutBox
- Spin Chat
- NAT1ON
Blom is the ajax instant messenger for our blog to keep the contact with your visitors. 
Gagalive adds a chat room anywhere HTML is allowed, such as your homepage, blog, forum, etc. It has a flexible API using secure chat room allows chat room nickname linkage to your membership system(drupal, phpBB, vBulletin, etc). 
Cbox is a unique commenting and chat widget that combines the best features of regular chat and tagging systems into one ideal solution. And the best part – Cbox Basic is completely free. 
Shoutbox a.k.a tagboard/chatbox, is an easy to use messaging system that allows you to interact with others instantly. 
Shout-Box.com offers a FREE, remotely hosted, AJAX powered ShoutBox for your Web Site / Blog / Forum etc. Easily place a Shout Box on your site so your visitors can leave messages for others to see. 
Yellbox provides an instant feedback from visitors your would not hear otherwise and allows your visitors to communicate or help each other. 
A freeshoutbox is a box where your visitors can leave their messages directly on your site. It is similar to a chat, but the messages are also stored like in a guestbook. 
With MyShoutbox, you develop a personal relationship with your visitors and thereby give them incentive time and again to visit your site. The hits to your website increase constantly! 
All you have to do is sign up for a free shoutbox, then put one line of code on your website. All your visitor has to do is type in their name and message and hit the shout button. They never even leave your web page. 
YShout is a lightweight yet full-featured package that allows you to easily add an interactive shoutbox to your website.A shoutbox is a great tool to communicate with your visitors and YShout allows you to chat with them in real-time. 
This is a PHP chat-box with integrated spam protection. It supports smilies / multiple languages and can be used with or without a MySQL database. 
A free PHP + Ajax shoutbox (chatbox, tagboard or mini chat). 
A V3 Chat is a chat-like feature that allow people to quickly leave messages on your website, without requiring any user registration. They are a great way to increase your online community and offer your visitors/members the ability to instantly communicate on your website. 
A free-shoutbox is a mixture between guestbook, forum and chat. The visitors of your homepage can send you news, make comments and also exchange news with each other. 
Flash Shoutbox is a flash aplication that make your visitor easily interact with you. Place it in your main page or all page, and let your visitor leave their short message. 
You have an own chat on your homepage, where people can talk or play games! 
Join NAT1ON and get a FREE soapbox for your site where visitors can leave INSTANT feedback and even participate in a real time conversations with other visitors.