The downside to this is that it's hard. This kind of service requires a sprawling infrastructure with many dozens of servers and tens of thousands of dollars in costs per month. And the amount of programming work to take that code-base and make it just work, plug-and-play, on someone else's machine for individual use, or in a larger set-up for shared use, is pretty serious. Not to mention that the many individual services powering such a service are often reused and tangled up in other (critical) services run by a company, and it's not always possible to separate out the intellectual property.
This is only a sampling of the issues - open-sourcing huge projects is actually much trickier than you might think!
Releasing their source does not imply that they are providing a working turn-key product that another company or individual could just one click install and have Digg back. Put it out there so the next generation has the opportunity to learn from their experience as well as their mistakes.
That said, you are absolutely right. Software at scale is complicated and often difficult to deploy and maintain. I just feel that this is not a barrier for open-sourcing their product.
> Releasing their source does not imply that they are providing a working turn-key product that another company or individual could just one click install and have Digg back.
Except that exactly what most people will want and get mad if it's not easy to run. The backlash from that isn't worth it.
> I just feel that this is not a barrier for open-sourcing their product.
IP alone can be a bitch and that coupled with the fact that a number of companies have secrets (key/tokens/passwords/etc) in their code and cleaning those out (AND removing the git/svn history) is no small task. Lastly there are number of open source RSS readers out there, I seriously doubt Digg was doing anything particularly innovative in this space and I don't imagine many people care to build on something they made 5 years ago and probably didn't update much since then. Especially if it's not built with the "New hotness".
This is only a sampling of the issues - open-sourcing huge projects is actually much trickier than you might think!