which mod is this ?

[-Captain Ghost-]

please help me in identifying this mod.

[shadow82x]

Could easily be someones custom code, but its not too different from something like: http://custom.simplemachines.org/mods/index.php?mod=3397

Key search terms: guest message box, welcome message, etc.

[Storman™]

You can ignore whats written in the box as it's configurable.

The actual mod is "Invitation Message In Your Face [IMIYF]"

http://custom.simplemachines.org/mods/index.php?mod=3107