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ehh. unless reposting to the other website naturally creates more backlinks (e.g. each site has its own separate audience that would increase the total number of backlinks) keeping the articles on separate sites and interlinking with keyword anchor text is probably the better strategy. content syndication works best when republishing to a new audience, on domains you don't already own.

The correct way to use UTM tracking without hurting your SEO efforts is to make sure you’ve implemented your canonical tags correctly. You should add self-referring canonical tags, which will prevent multiple versions of the same page from being indexed. For example: http://www.yoursite.com/some-page?utm_source=facebook&utm_medium=social should have a canonical tag that looks like this: If you have pages with these parameters on your site then you should use the rel=”canonical” tag to specify the canonical URL that you’d like Google to rank. I hope this information answers your question. if you consider that my answer is good enough don't  forget to mark it as a Good Answer Regards and have a great day