There is no such big-ish projects using Guile outside projects embedding Guile and guix. There is no wordpress or even framework as powerful and easy to use as Django or Rails. There is no support for https, it's kind of a no-go if you want to access REST APIs from Guile. Cookie support is not good enough. That said, the creator of Artanis reported some success using Artanis in a commercial setting. Outside that there is various free projects in the work, look at Guile homepage or ask on #guile. On my side I am working on search engine named Culturia.