It doesn't have a catchy name, and people generally refuse to talk about it because this particular penalty requires taking responsibility. It's much easier to blame the +-30 penalty, the Sandbox or the new 950 penalty than it is to accept that you've been nailed with the most common penalty of all. What is it you ask?
It's the My Site Sucks Ass And Google Just Figured It Out penalty.
Let me 'splain what it is and why it occurs. It's at least as plausible as half of the half-baked theories out there at the moment.
It's quite simple really. Google gives webmasters a chance. Also known as 'give them enough rope'. Sites start out with an idea and a hardworking webmaster. But somewhere along the way, the content ends up being a remash of all the content that has gone before.
Ads take over content real estate. So A Widget Forum is added. And a Widget Resource page, and a Widget Directory, and soon, the site is just a replica of all the other widget sites. With fewer links and a bored webmaster. In short, the site sucks ass. But there for awhile, Google couldn't tell that it sucked ass. So they waited. (see, Give Them Enough Rope above).
Unfortunately, the benevolent Google god's patience inspires hope in the poor Webmaster. Google loves me! This is easy! Then, when the wrath of the Google Gods is unleashed upon the poor faithful, they, like humans have for centuries, blame everyone but themselves.
It must be OOP, or the +-30 Penalty, or the 950 Penalty, or a Commercial Terms filter, or a new LSA filter. Maybe if I light a candle and say a Hail Sergey? Anything but the dreaded truth. My Site Sucks Ass And Google Just Figured It Out.