SEO Penalty ↔ List of penalties by Google | Bing
Seriously, what's up with these dumb animal names for google algos/penalties?! Google attempt to come across as cute?!
Google Penguin
Google Algo to fight against paid links, low-quality Anchor Text Optimization, Keyword Stuffing
Google Panda
Keyword Stuffing
to spam Web Page with lots of repetitive keywords in attempt to boost SEO rank/relevance to specific search phrases