OP here. And not necessarily. You can be "over-optimized" without being spammy.
Over-optimized refers to having your SEO optimized to rank for a very specific, targeted term. Take "trolling motors" as that's the site of mine that was penalized.
Even if I built all my links via white hat, legi methods - but the anchor text of all the links to my home page said "trolling motors" - I'd likely be penalized. That's because in a naturally linking backlink profile, people would link with a wide variety of different words, not just "trolling motors". Because the concentration is so focused, it's almost a guarantee that someone was trying to game the system. Google algorithm updates like Penguin have really started cracking down where's it's obvious the owner is trying to rank for a word by optimizing the links, title, headings, copy in a way that appears dramatically non-natural.
Often, however, spammy link campaigns are also over optimized as well.
I would take it to mean that they basically went too far past the gray area of "legitimate" SEO in any or all areas. Spammy links, low quality links on "link farm" sites, keyword abuse, etc.
Over-optimized refers to having your SEO optimized to rank for a very specific, targeted term. Take "trolling motors" as that's the site of mine that was penalized.
Even if I built all my links via white hat, legi methods - but the anchor text of all the links to my home page said "trolling motors" - I'd likely be penalized. That's because in a naturally linking backlink profile, people would link with a wide variety of different words, not just "trolling motors". Because the concentration is so focused, it's almost a guarantee that someone was trying to game the system. Google algorithm updates like Penguin have really started cracking down where's it's obvious the owner is trying to rank for a word by optimizing the links, title, headings, copy in a way that appears dramatically non-natural.
Often, however, spammy link campaigns are also over optimized as well.
Hope this helps!