If your blog is listed on Bloggingportal (you can check here) then you can use the “I’m listed on bloggingportal.eu” badge on your blog. This helps promote the portal.
Jon Worth has created the one below which you can use. Or you create your own version (and post a link to it in the comments). There are also raw versions (including vector format) of the bloggingportal.eu logo available for download.