Originally Posted by AmeliaG

I'd recommend using self-hosted Wordpress i.e. install Wordpress on your own domain. Wordpress.com is more analogous to Tumblr.com and there are slight benefits to an existing user base there. I doubt that user base is your target audience though. While either one has functionality for using your own domain, Wordpress is infinitely more robust for commenting than Tumblr. You can customize plug-ins for special functionality if you host Wordpress yourself. So definitely either your own Wordpress install or Wordpress.com.