Yes on the old answerbag site when they began taking advertising from Google AdSense that company insisted that anything not "family-friendly" on the site be deleted so over two or three years many of my best posts, mostly concerning sex and sexuality, were removed. Interestingly when that site reopened under a new owner some of them appeared again!
On this site there have been posts of mine which have not been allowed by the owner or moderators because they did not accord with their published rules for the site. Which they have every right to do. Because I am here as their guest.
But mostly I try to avoid censure by censoring myself.