Mailing List Archive

Hi,
jspen.co is a tool to create urls that contains html/Javascript content.
An url example (it will run an alert) is https://jspen.co/#JTNDIURPQ1RZUEUlMjBodG1sJTNFJTNDaGVhZCUzRSUzQ3RpdGxlJTNFTmV3JTIwUGVuJTNDJTJGdGl0bGUlM0UlM0NtZXRhJTIwbmFtZSUzRCUyMmF1dGhvciUyMiUyMGNvbnRlbnQlM0QlMjJBbm9ueW1vdXMlMjIlM0UlM0NzdHlsZSUzRSUyRiolMjBDU1MlMjAqJTJGJTNDJTJGc3R5bGUlM0UlM0MlMkZoZWFkJTNFJTNDYm9keSUzRVRFU1QlM0NzY3JpcHQlM0UlMkYlMkYlMjBKYXZhc2NyaXB0JTBBYWxlcnQoJTIyVEVTVCUyMiklM0MlMkZzY3JpcHQlM0UlM0MlMkZib2R5JTNF

This tool is abused by spammers as a redirector, any idea how to block its abuse other then block the domain ?
Thanks
Giovanni