Trying to understand the difference between the two and what scenarios it'd be best to use them in.
I'd get a Pownce or Twitter account but I don't have any friends. ;)
EDIT -- looks like I figured it out myself. ;)
Put SkyNet on top of Starling and off to the races you go.
SkyNet can be configured to use different message queue systems. Starling is just such a message queue system, apparently robust enough to run Twitter (or not, when Twitter's down).
SkyNet -- implementation of an algorithm Google uses for distributed computing.
Starling -- what Twitter uses.