There are a couple ways blogs show up on your "Manage Blogs I'm Following" page. Through Blogger you can follow a blog via the following gadget on the blog or you can add the blog directly to your Reading List. Blogs will also show up on your "Manage Blogs I'm Following" page if you've joined a site with Google Friend Connect.
From the "Manage Blogs I'm Following" page, you can edit your settings for each blog you are following. To do so, click the "Settings" link next to the blog you want to edit. You will then be shown a pop-up page with your profile and the settings for that particular blog:
You can then select to stop following the site, select to follow the blog anonymously or publicly, and select to publish your activities to other sites you have joined (this setting will display this particular blog with your profile on the other sites you have joined).