I am telling my experience back in 2017. In 2017 backlinking through forum posting and comment posting is well know and commonly used SEO technique. Now a day I didn’t know if someone is using this technique.
Most of the forum and websites used Akismet as spam protection. Whenever we try to post content with a link (my pure intention was to backlink). Unfortunately Akismet will not allow me to post the link or comment.
SEO Myth: Akismet will not permit any one to post comment or link without the permission of admin. If a link is present Comment will be under review.
SEO Reality: I will post a comment with link to a forum or website (if moderator has no crucial role). How Its Happens!!!!
I came to notice that Akismet have a loophole, if we are posting a comment with guest website URL along with host website URL, automatically Akismet allow posting that comment. I think Because of host website URL Akismet gets confused. So it will permit the comment.
Lots of time i have used this technique!!!