Nowadays many companies and organizations (non-profits, units of governmental and educational institutions, etc) believe that running their own mail servers has become an impossible task, due both to the large amount of inbound spam and to the continuous attempts by spammers to send outbound spam through their mail servers. Companies often lack in-house technical resources to configure and run a mail server properly and deal with these threats. For these reasons, many organizations decide to outsource their email service to external entities.