Podio is an interesting Project Management and Team Collaboration web app.  The following article is an interesting review of Podio on businessinsider.com

 Podio: A Collaboration Application That “Does It All”

It should be noted that Podio was not developed by Citrix, but Citrix recently purchased the company.

Podio, from CrunchBase

Podio, now part of Citrix, is a collaborative work platform with a new take on how everyday-work gets done. Podio gives people more power than they’ve ever had before to manage their work better, smarter and in their own way.

Combining hundreds of specialized and flexible work apps with messaging, tasks, reporting, workflow and contact management, Podio lets you build and shape the online workplace most fitting to your role. It eliminates scattered, unorganized work routines, and replaces multiple products from different companies with a single environment and a single login.

A key feature of Podio is the ability to have apps developed by the users.  This sounds very interesting.  You can also use apps developed by others, when made available in the marketplace.