Before the BBS era of the 1980s phone phreaking was more of a solitary venture as it was difficult for phreaks to connect with one another. In addition to communicating over BBSs phone phreaks discover voice mail boxes and party lines as ways to network and keep in touch over the telephone. They usually appropriate unused boxes that are part of business or cellular phone systems. Once a vulnerable mailbox system is discovered, word would spread around the phreak community, and scores of them would take residence on the system. They use these systems as a "home base" for communication with one another until the rightful owners would discover the intrusion and wipe them off. Voice mailboxes also provide a safe phone number for phreaks to give out to one another as home phone numbers and personal cellular numbers would allow the phreak's identity (and home address) to be discovered. This is especially important given that phone phreaks are breaking the law.