I devote a lot of attention to groupware systems that could be integrated into Pluto. Today, also family is little company to run, so I guess that light groupware (calendar,addressbook, todo lists, ...) is more than welcome in such system.
Currently I checked newbielink:http://www.egroupware.org [nonactive] and it has made tremendous development. All datas are stored in mysql, and they have great web interface - particularly this one looks interesting:
I wonder if anyone else is thinking about candidates for groupware functionlity in Pluto and how to implement it...