http://www.inkalinux.com/foros/showthread.php?117-Como-bloquear-Youtube-Facebook-en-mikrotik-usando-L7-100-efectivo-)
/ip firewall layer7-protocol
add comment="" name=facebook regexp="^.*(facebook).*\$"
/ip firewall layer7-protocol
add comment="" name=youtube regexp="^.*(youtube).*\$"
/ip firewall filter
add action=drop chain=forward comment="" disabled=no layer7-protocol=facebook src-address=10.26.13.218
/ip firewall filter
add action=drop chain=forward comment="" disabled=no layer7-protocol=youtube src-address=10.26.13.218