Multi-hop - aka chaining VPN servers - is that you connect through multiple servers, just like with Tor. The advantage multi-hop gives is that the adversary has to deal with multiple jurisdictions before he/she can get to the VPN user. It would be nice if cryptostorm could add an option to route VPN traffic through at least three VPN servers in different countries, for increased privacy.
According to That One Privacy Site's VPN Comparison Chart (link
) there are currently 18 VPN services that support multi-hop: AirVPN, Astrill, CryptoHippie, Doublehop.me, I2VPN, In-Disguise, Insorg, IVPN, NordVPN, oVPN.se, oVPN.to, Perfect Privacy, Proxy.sh, SlickVPN, VIP72, VPN4All, WindScribe, and ZorroVPN.