You have just installed the Disqus comment system on your WordPress blog and now you see it appearing all over the show, on both pages and posts alike. I ran into the same issue and for obvious reasons only wanted to show it on single blog posts and would love to share how I fixed this with you.
There are only two simple steps so be sure to do exactly as I explain.
Step 1
Disqus is added to your posts and page alike through the WorPress ‘comments_template’ filter. In order to override this we will have to disable this filter from being called by the plugin. To do this add the following code to your theme’s functions.php:
https://gist.github.com/6607344.git
This will only disable Disqus, but will still show the default comment system, which we’ll remove in the next step.
Step 2
The final step will simply be to remove the default comment system from pages as well. To save you some time there is already a plugin that does this: http://wordpress.org/plugins/disable-comments/
After installing and activating this plugin. Go over to the settings and make sure you select by post type option ensure that only blog posts are unchecked ( meaning comments will be hidden for the checked post types).