It can be modified by editing the values passed to shockwave in the HTML source of this page:

<!-- ----------------------------------------------- --> 
<!-- alan's shockwave sneaker
     may be freely used but not charged for, 
     we like to get credit, stroke our egos!                           

     You can modify the effect be editing the values
     in the OBJECT and EMBDED tags as follows:
     
     sw1     the final message that appears
     sw2     a fudge factor for how long it takes
             for the sneakering to occur. Each letter
             gets an iteration =random
               sw2 + 10 * random(sw2)
     sw3     the size of the courier font; longer strings
             will need smaller font sizes and watch out for
             the difference on Mac versus Windows systems!
             
                                                     -->
<!-- ----------------------------------------------- -->                                                     
<!-- OBJECT tag used by Microsoft Internet Explorer  -->
 
<OBJECT CLASSID="clsid:166B1BCA-3F9C-11CF-8075-444553540000"
CODEBASE="http://active.macromedia.com/director/cabs/sw.cab#version=6,0,0,0" 
WIDTH="480" HEIGHT="80" NAME="nojava" ID="swmovie1">
      <PARAM NAME="SRC" VALUE="sneaker.dcr">
      <PARAM NAME="BGCOLOR" VALUE="#FFFFFF">
      <PARAM NAME="PALETTE" VALUE="background">
      <PARAM NAME="sw1" VALUE="Director geek!">
      <PARAM NAME="sw2" VALUE="30">
      <PARAM NAME="sw2" VALUE="36">
      <PARAM NAME="swLiveConnect" VALUE="FALSE">
      
<!-- EMBED tag used by NetScape Navigator  --> 
<embed src="sneaker.dcr" width=480 height=80 bgcolor=#FFFFFF 
       sw1="Director geek!"
       sw2="30"
       sw3="36"       
       pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveDirector" 
       swLiveConnect="FALSE">
</OBJECT>