Came across Zimbra… very impressive open source app.. I was blown away with what they were able to get the browser to do…

In its current form it is a really nice messaging system… They have a model for allowing 3rd parties to plug into their ui, adding actions/meta data about “stuff in email” such as an order number, person’s name, etc..

Seems this open source model of building free products and selling support and customizations is getting more traction.