In this week’s Top 5, we highlight open source alternatives to Google’s Picasa for organizing your photos, a cutting-edge math tool for the classroom called SageMath, ownCloud’s collaboration with CERN and AARNET to reach it’s next milestone, and a two-part series that examines SourceForge Media’s recent past and future plans and the considerations ownCloud CEO Frank Karlitschek had to make when selling his first startup.

Top 5 articles of the week

5.When selling a site means selling a community

The top #5 and #4 spots in the list this week are part of a two-part series where Rikki Endsley examines the question, “What happens when selling a site means selling a community?” In the first article, she looks at the considerations ownCloud CEO Frank Karlitschek had to make when selling his first startup, a network of open source community sites.

4.Still reeling, SourceForge looks to the future

In the second article, Rikki Endsley interviews Logan Abbott, President at SourceForge Media, which is the company that now owns SourceForge and Slashdot, about their recent past and plans for the future.

3.Open collaboration, CERN’s particles, ownCloud, and petabytes

This is the story of ownCloud’s collaboration with the IT team behind the largest particle physics laboratory in the world, the European research organization CERN, as well as Australia’s countrywide networking provider for research institutions, AARNET (Australia’s Academic and Research Network).

2.Open source math software competes in the classroom

Creator of SageMath, an open source mathematics software system, William Stein tells us how teachers can now easily use Python and R in their courses and collaborate in real time to manage their online courses with the same cutting edge software used by top mathematicians at the best universities in the world..

1. 9 open source alternatives to Picasa

Google is shutting the doors on the Picasa desktop client next week, but Jason Baker tells us about at least 9 of the open source alternatives out there for your photo organizing needs.