User Modes

Mode Description Restrictions
B Adds a line in WHOIS replies marking you as a bot.  
d Only see messages prefixed with the `!@$. character (Used to reduce traffic for bots).  
D Only receive private messages from network operators, servers & services.  
H Hide IRCOp status in WHOIS replies. IRCOp-only
I Hide online time in WHOIS replies. IRCOp-only
i Hidden from WHO & NAMES if queried by someone outside the channel.  
o IRC Operator Set by server
p Hide channels in WHOIS replies.  
q Unkickable. IRCOp-only
r Registered nick. Set by services
R Only receive private messages from registered nicks.  
S Services bot. Services-only
s Receive Server notices. IRCOp-only
T Prevents receiving CTCP's.  
t VHOST has been set. Set by server
x Use a cloaked hostname.  
Z Only able to send/receive private messages/notices/CTCP's with people using SSL/TLS.  
z Connected using SSL/TLS. Set by server