obfu-quicky is from 2000-06-27. Next, Re: J.A.D.N.A. links to a file called obfu.pl and passes it a parameter obfuID=2 (2000-12-27). Third is Re: Node 541 on 2001-03-07 at which point the appearances really start to pick up (Re: Re: Re: Icarus on 2001-03-23, Do the dishes on 2001-04-03, 3 more that month, 21 the next month, 24 the next, 23 the next, etc.)

But before any of those, the PerlMonks source code and the HTML output by User Settings included several variables like "fp_max_obfu" probably starting around 1999-12-31 when the obfu section was being added to PerlMonks.