Chitter is basically email for your website.
I recently launched Chitter with the hopes that it could stand out from conventional messaging services that are more focused on product support and answering immediate questions regarding pricing. Chitter is better for engaging with users over the course of days, weeks, or months - really the user's entire life cycle. This way, you can really learn who your user is and what they want.
As previously mentioned, I just launched, as in last night. Features are seriously lacking at the moment but I'm adding to it day after day. If you try it out, let me know what you think!