Gopher is correct. The Society restricts distribution of the WT CDROM largely as a matter of control. It is an official rule, published in Kingdom Ministry, that Watchtower Library is for internal use. Any person can walk in off the street to pick up "regular" literature at the literature counter in the Brooklyn Bethel Furman Street facility. However, to get the WT CDROM you have to show a "blood card". Same goes for the Proclaimers book and the bound volumes. Congregations are officially supposed to restrict distribution of such literature. However, individual JWs can override the official policy if they feel that an "interested person" will use such material "properly". Experience shows that individual JWs will also try to prevent those who they feel will "misuse" such material from getting it.
AlanF