[_ck_]

Cookies have nothing to do with reading the forum (unless there’s a hidden/private forum). Cookies are about identifying yourself as a registered member and giving you the ability to post. But a secure login method and cookie means that no-one else can pretend to be you.

The mini-plugin is to prevent Google from showing a “cache” link on your pages when people find results from your website. They’ll have to visit your site directly, and if it’s a hidden/private forum, they won’t be able to just read it through Google’s cache (which can’t see it anyway, unless someone changes “Hidden Forums” behaviour).