At the moment, I can serach for a tag only in those blogs, which are configured to a specific language by its owner.
http://en.wordpress.com/#!/read/topic/street-photography searchs postings with this tag within English blogs only.
http://de.wordpress.com/#!/read/topic/street-photography searchs postings with this tag within German blogs only.
http://wordpress.com/#!/read/topic/street-photography (without the language prefix) searchs postings with this tag within German blogs only too (because my blog is a German blog).
I would like to search postings with a tag within all wordpress.com blogs, regardless of the blog's language.
The blog I need help with is nummervier.wordpress.com.