I found a free application called Elgg. It's my understanding that people frequently program custom interfaces on top of this software.

I'm wondering if anyone has programmed a setup with this software that works in a manner similar to Yahoo Groups?

I've seen some web sites using it that have discussion groups, similar to Yahoo Groups web interface, but I'm not clear if anyone is also using it as an e-mail based discussion list tool.

If you have other solutions that work in a manner similar to Yahoo groups free or paid, please mention them.

I'm able to entertain a solution that involves custom programming, but don't have the resources to create this type of solution from scratch.

A forum environment could suit many of the requirements for the web interface, but it seems most forums fail at e-mail integration (can't find any post / reply via e-mail integration for VB, only a couple discussions of interest in it).

I feel it would be preferable to use regular forum software with built in notification. However, I am looking at this solution for some existing yahoo groups that will be highly reluctant to switch to a fully web based solution.

Thanks for any input.