I've found what you were referring to before - once a post hits a payout of $10, the links within the post can then be read by web spiders - in technical terms, by default, a link within your post has a "nofollow" attribute which changes to "follow" once $10 is linked. I'm not sure I've explained it very well but hopefully you get the gist.

So linking to your other articles would benefit them if your post reaches $10.

I've read quite a lot about it this morning and found an old post by steemitblog which talks a little bit about SEO. The idea of "the canonical URL" and how duplicate (sometimes plagiarised) content damages a site's SEO is something I've subsequently looked into.

A few years ago, there was some interest in Steemit and SEO which I'd like to look into more when I have some time. Steemit once ranked in the top 1,000 for Alexa Site Rank.... it's now nearly at 4,000 and is falling rapidly.