Complex sentence: By the end of 2006, the number of items sent to 10048 had decreased to around 300 items daily, mostly sent from businesses and organizations that had not yet updated their bulk mailing lists.
Split into simpler sentences: By the end of 2006, the number of items sent to 10048 had decreased to 300 items daily. The mail is mainly coming from businesses and organizations that have not updated their bulk mailing lists.