I would like to turn the comments to dofollow on my wordpress.com blog but I can not find the way and after my search on your above button I can not find relevant support, they all concern the .org where it is easy to do but with a .com public free service it is not the same as I can not neither add plugins nore change php code.
If you have the solution, please let me know asap, thank you
That’s not possible on a free hosted WordPress.com blog. You need to hire a web host and set up a WordPress.org install to accomplish rewarding every commenter with a do-follow link. Please read this carefully so your are clear on the differences between free hosted WordPress.com blogs and self hosted WordPress.org installs. http://support.wordpress.com/com-vs-org/