How many time should I post on sites like Medium and SlideShare?

How many times should I post on Web 2.0 and document sharing sites to get a backlink.

I created an account with Medium and SlideShare.

Should I post once on Medium, add a backlink to my homepage and move on? Or, should I post a new article with a backlink to every article on my website? So then I have at least one backlinks to every page on my site from Medium?

Same question for SlideShare. Do I post once, move on, or add a slideshow for every article on my site, add in a backlink and…

How many time should I post on sites like Medium and SlideShare?