WorkingOnIt Linden is a way for us to show us that Issue Tracker stuff is being worked on, instead of showing an uncomfortable "Unassigned" status.
WorkingOnIt will also make comments and updates as we have news to share.
WorkingOnIt can be used by any Linden, but Torley started manning the account on 2007-04-30 as an experiment.
As we improve the Issue Tracker (also known as "Public JIRA" or "PJIRA"), we want to sync up internal and external info better. Currently, on our internal JIRA, when a Linden assigns themselves to an issue, it doesn't get automatically mirrored on the Issue Tracker. Also, there isn't an easy way to show that a group of Lindens are working on an issue. All that minutiae gets tedious.
Using WorkingOnIt Linden provides visibility that yes, we're making progress on something, while saving time that could be better spent resolving the issues themselves.
What does it mean?
If an issue is assigned to WorkingOnIt Linden, it means exactly that — an issue is either actively being worked on or "on our plate" to get to soon. These issues will also be resolved like any other when done.
If an individual Linden would rather assign themselves specifically to an issue, they can also do that. But again, this is a general and easy method of telling you an issue is officially having progress made!