This add-on automatically removes all garbage like "utm_source=*" from URLs. These fields are provided for the Google Analytics and they are not a necessity.

Example of URL with garbage fields:
http://bigpicture.ru/?p=431513&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+bigpictures+%28%D0%9D%D0%9E%D0%92%D0%9E%D0%A1%D0%A2%D0%98+%D0%92+%D0%A4%D0%9E%D0%A2%D0%9E%D0%93%D0%A0%D0%90%D0%A4%D0%98%D0%AF%D0%A5%29

Pure URL:
http://bigpicture.ru/?p=431513

Pure URL removes these garbage fields:
— utm_source, utm_medium, utm_term, utm_content, utm_campaign, utm_reader, utm_place and all of this with ga_ prefix (spyware fields for the analytics.google.com)
— _openstat (spyware field for the openstat.ru)
— yclid (spyware field for the metrika.yandex.ru)
— feature (a garbage field on the youtube.com)
— fb_action_ids, fb_action_types, fb_ref, fb_source, action_object_map, action_type_map, action_ref_map (spyware fields from the facebook.com)
— ref, fref, hc_location (garbage fields on the facebook.com)
— ref_ (garbage field on the imdb.com)