Open Source Software
Social Networking is what's really hot and happening and why shouldn't it be? You can interact, manage and be in touch with all your contacts at one single place that also sitting on your couch having your cup of coffee with a cookie may be.
In my article on Top 10 Customer Relationship Management Software, I had highlighted one of widely adopted open source software - Sugar CRM.
Cyn.in (pronounced as sign in) is a web based enterprise service which is a blend of blog and wiki (preferably called bliki by them).
Db4o is an excellent open source object database for Java & .NET platform by Carl Rosenberger's team.
