Robert_Charlton - 11:35 pm on Apr 24, 2012 (gmt 0)
To conjecture about the "Again" part of the title... for me, anyway, these ongoing narrowly-targeted updates confirm more than ever that AI (Artificial Intelligence) is actively being used in the algorithm.
Why do I say that?... because, when using AI, it's important for engineers to correlate what they're targeting with the effects they see. Thus, I'm assuming, the updates are grouped together in chunks reflecting types of sites or situations Google is going after... with a degree of focus necessary to isolate cause and effect.
With regard to large collateral damage apparently being reported, I can only guess that Google initially needs to push things a little too far, not only to bring all the junk to the surface, but also to observe what kind of collateral damage is happening so they can fix it in a timely fashion. Otherwise, I'd assume, there would be a greater risk of longer term collateral damage that would go unobserved.
I'm assuming we'll see pendulum-like swings, as with any feedback system, as corrective actions are taken and the algo zeroes in on what it's targeting.
Conceivably also... still guessing... the value of upstream inbound links to some sites might be affected, which would affect downstream sites. In some cases, you might have inbound links from sites that are taken out, and it may not be your fault. Whether that's going to be calibrated to protect the innocent isn't clear. I would expect that Google certainly has thought about these considerations.