Modes

IRC / Server / Modes

User modes:
+I - Hides all channels from other users in /WHOIS.
+R - Prevents messages from non-registered users.
+S - Enables stripping of IRC formatting codes from private messages.
+T - Prevents you from receiving CTCP requests.
+c - Requires other users to have a common channel before they can message you.
+i - Hides you from /WHO.
+l - Hides idle time from other users in /WHOIS.
+o - You are now an IRC Operator.
+r - Marks that your nick is registered.
+w - You can receive WALLOPS.

Channel modes:
+C - Blocks CTCPs, other than ACTION, from the channel.
+I - Exempts users matching mask from the (inviteonly) channel mode.
+M - Users must be registered with services to speak in the channel.
+O - Makes a channel as 'IRC Operators only'.
+R - Users must be registered with services to join the channel.
+S - Enables stripping of IRC formatting codes from channel messages.
+T - Prevents any notices to be sent to the entire channel.
+b - Bans the matching mask from the channel.
+c - Blocks messages and notices with colour or formatting codes.
+e - Exempts users matching mask from the (ban) channel mode.
+f - Allows to set a mode on channel which prevents message/notice flooding.
+i - Prevents users from joining the channel without an invite.
+j - Allows to set a mode on channel which prevents join flooding.
+k - Sets a password required to join a channel.
+l - Sets the channel limit. Once the limit is reached, no more users can join.
+m - Makes a channel 'Moderated'. Users need to be +v or higher to talk.
+n - Prevents external messages, users must be on channel to talk.
+p - Sets the channel as 'Private'. Will not show up in /LIST.
+r - Marks a channel as registered with services.
+s - Sets the channel as 'Secret'. Will not show up in /LIST or /WHOIS.
+t - Prevents non-channel operators from changing the channel topic.
+z - All users must be connected to the network via SSL to join the channel.