Who plays under which rules?

Who plays English language Scrabble under which Rules?
OSPD OSW SOWPODS
double-challenge Canada
Israel
Mexico New Zealand
Thailand
US
10pt-challenge Malta* *
5pt-challenge Singapore
single-challenge Ireland Australia
UK Bahrain
Malaysia
Philippines
Sri Lanka
unknown African nations
Bermuda
India
Qatar
Japan

+-----------------------+
|<PRE>-formatted version|:
+-----------------------+
                           OSPD       OSW         SOWPODS

    double-challenge      Canada
                          Israel
                          Mexico                 New Zealand
                         Thailand
                            US
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      10pt-challenge      Malta*                      *
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       5pt-challenge                              Singapore
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    single-challenge                 Ireland      Australia
                                       UK          Bahrain
                                                  Malaysia
                                                 Philippines
                                                  Sri Lanka
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
             unknown                           African nations
                                                   Bermuda
                                                    Qatar
                                                    Japan
* Malta is in transition from OSPD to SOWPODS. A few more, and you could appropriately call it a movement.
My source for this technique, http://www.mtsu.edu/~cosc0065/schedule.html:
Spring '97 Schedule
Sun Mon Tue Wed Thu Fri Sat
8am              
9am     *Wood *   *Wood *    
10am   BMOM233 *Wood * BMOM233 *Wood * BMOM233  
11am   CSCI413 *Wood * CSCI413 *Wood * CSCI413  
12pm   ENGL223   ENGL223   ENGL223  
1pm   *Lyon *          
2pm   *Lyon *          
3pm   *Lyon * *Wood *   *Wood *    
4pm *Lyon * *Lyon * *Wood *   *Wood *    
5pm *Lyon * *Lyon * *Wood *   *Wood *    
6pm *Lyon *            
7pm *Lyon *            
8pm *Lyon *            
9pm *Lyon *            
10pm              
11pm