Miniforum/Reaction-widget for your website or blog, very lightweight, no need for a webserver with PHP/ASP/Perl or alike; you can use this mini-forum from plain-HTML websites and you won't need a database (I will take care of the database-stuff for you), no need for Captcha’s (or at least as long a there’s no robot out there smart enough for interpreting javascript), implemented in just a couple of lines of code, threaded messages, Skinnable :you can change the looks by using your own CSS, uses no iframes, and it's fully hosted; won't take any of your bandwidth.