I have read that Penguin is keyword specific, meaning Google penalize the site that over optimized for the keyword, but for the keyword only and it does not affect the authority of the site or other keywords, is it correct?
If that's the case, if you forget about the original keywords(which penguin hit), and make the site again with other/new keywords, you are safe?
The reason I ask this is that I am thinking of making an authority site using the silo structure with the same theme. Even though my site was hit by Penguin with 2 main big keywords, there are many other small - middle keywords I can optimize and lead to conversion under the big theme.(e.g. if "learn piano" was the original keyword which was hit, now use "piano beginner" or "how to play the piano" or something like that - using for the homepage or sub pages). Luckily(?) I only optimized for 2 specific keywords.
If Penguin does not affect domain authority, I thought I would better off using the same domain than using a completely new domain because the domain age is 10 years and the page rank is 3.
Any advice would be appreciated