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Happy Holidays to you, too! It's possible that the penalty is related only to the duplicates, but the process I described above should help uncover whether that's the case. It's definitely worth cleaning up the domains you owned that are duplicates rather than 301s. As for the other older links - it depends on how bad they are, how many there are, and whether you think there's risk that Google may penalize you for them. Unfortunately no easy answers there. SEO isn't the only inbound channel! Social media, blogs, building an email list, content marketing, etc. are all options, too. I like targeting hihgly relevant, rarely searched phrases. The CPCs tend to be lower and the quality of leads higher. And working on conversion rate is a great idea since that helps all kinds of traffic. Wish you all the best!