Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

MarsEdit - MarsEdit is a desktop blog editing application for the Mac. It provides an offline interface to most popular blogging systems. WordPress, Blogger, Tumblr, Movable Type, and many other systems are supported.

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

Drivel - Drivel is a GNOME client for working with online journals, also known as weblogs or simply...

Bigtent - BigTent is a web-based organization and communication portal for groups.

Open Live Writer - Open Live Writer makes it easy to write, preview, and post to your blog.