Are there any that do work? The two suggested at that link don't seem to. Outbrain is dead as far as I can tell (doesn't show up when I search for plugins) and Jetpack requests a separate Wordpress.com account, which I don't have.
Yeah, they're blacklisted because by the very nature of what related posts plugins do they are resource hogs. GoDaddy is not alone in having a list of plugins that are not allowed/approved on their platform.
Unfortnatley, I am not aware of any related post plugins that don't slow down the preformance of the site. Maybe someone else will pipe-in with suggestions that they've tested without negative impact.
It's easy to setup a WordPress.com account just to use JetPack (which is made by and for WordPress) to give that a whirl.
Judith "Today ends tonight and tomorrow starts again."