Guess that protocol...

gistfile1.txt

From: http://twitter.com/#!/datagrok/status/117094906115264513
/^(?::([^ ]+) )?([^ ]+)((?: [^: ][^ ]*){0,14})(?: :?(.*))?$/


/^                                                        $/  
match the left and right boundaries of the string (The entire string must be described by the pattern)                                                                             

  (?::([^ ]+) )?
Optional: No Back Reference*: a colon, one or more non-space chars, a space

                ([^ ]+) 
Back Reference: one or more non-space chars

                       ((?: [^: ][^ ]*){0,14})
Back Reference: a space, one non-space non-colon char, zero or more non-space chars, all occurring 0 to 14 times, occurrences not individually back referenced

                                              (?: :?(.*))?
Optional: No Back Reference*: a space, zero or one colon char, zero or more chars

*The use of the "(?:" non-back referenced parenthetical groups is an optimization benefiting both performance (speed and memory requirements) and complexity of down stream code. The array of matches will not include these and the code that processes the array will not have to skip over them.