Does anyone have solid proof of the so-called Over Optimization Penalty? And What would trigger this penalty?
Probably just means google considers you "trying to build links purposefully for Page Rank" or just thinks your backlinks are fake.
I imagine anything that doesn't look natural, that could mean many things, but all webmasters understand if they are over doing it a bit.
the only way to over optimize is onpage, and G will ignore stuffing etc nowadays. Off page is not optmization, it's trying to get links to out things in your favor and is covered by their link policies.
It is real to some extend. Depending on what exactly happen to your site. For example, if your site stopped advancing in SERPs for certain keywords despite more links being added, in short to many BL with same anchor text. Fast solution- adjusting anchor text ratio. Slow solution- do nothing, in time, your site will eventually start moving up again.
What do you mean by over optimization? Yes, they do exists. Like huge keyword density, ferocious link building etc.
I think its only when you go too hard trying to build links, especially doing 100s of links when the site is very new.
when you flowly make backlinks by one anchor text AND when google found that you are doing unnaturally. -Ishu