Finding closely affiliated friends. These queiries are built to operate on a small datasets at http://sqlfiddle.com/#!2/907b6/1. For work on a real wiki numbers in these queries will require fine tuning.

10 my top edits.sql

SELECT rev_page   
      FROM revision_userindex   
     INNER JOIN page ON page.page_id = rev_page  
     WHERE rev_user_text = "Jimbo Wales" 
       AND page_namespace IN (0,1)    
     GROUP BY rev_page 
    HAVING count(rev_page) > 20
     ORDER BY COUNT(*) DESC

20 related editors.sql

--
Select rev_user, rev_user_text, COUNT(rev_page)
  From revision_userindex
  INNER JOIN page ON page_id = rev_page 
 Where rev_page in 
   (SELECT rev_page   
      FROM revision_userindex   
     INNER JOIN page ON page.page_id = rev_page  
     WHERE rev_user_text = "Jimbo Wales" 
       AND page_namespace IN (0,1)    
     GROUP BY rev_page 
    HAVING count(rev_page) > 20
     ORDER BY COUNT(*) DESC
    ) 
 AND rev_user != 1
 GROUP BY rev_user
 HAVING count(rev_page) > 10  
ORDER BY COUNT(*) DESC
  LIMIT 6;

30 friend recommendation.sql

Select REV_USER_TEXT FROM 
( 
Select rev_user_text, page_title,COUNT(rev_page)
  From revision_userindex
  INNER JOIN page ON page_id = rev_page 
 Where rev_page in 
   (SELECT rev_page   
      FROM revision_userindex   
     INNER JOIN page ON page.page_id = rev_page  
     WHERE rev_user_text = 'Adam' 
       AND page_namespace IN (0,1)    
     GROUP BY rev_page 
    HAVING count(rev_page) > 2
     ORDER BY COUNT(*) DESC
    ) 
 AND rev_user != 1
 GROUP BY rev_user,page_title
 HAVING count(rev_page) > 2   
ORDER BY COUNT(*) DESC
  ) PALS
GROUP BY rev_user_text
HAVING COUNT(rev_user_text)>1
LIMIT 4 ;

99 the db schema and testing data.sql

CREATE TABLE  namespaces( `i` int(11) unsigned, `v` blob);
INSERT INTO namespaces VALUES (0,''),(1,'Talk'),(2,'User'),(2,'UserTalk');

CREATE TABLE page
(
 `page_id`           int(8) unsigned,
 `page_namespace`    int(11),
 `page_title`        varchar(255),
-- `page_restrictions` tinyblob,
-- `page_counter`      bigint(20) unsigned,
-- `page_is_redirect`  tinyint(1) unsigned,
-- `page_is_new`       tinyint(1) unsigned,
-- `page_random`       double unsigned,
-- `page_touched`      varbinary(14),
-- `page_latest`       int(8) unsigned,
 `page_len`          int(8) unsigned
);
INSERT INTO page VALUES 
(0,0,'Apple',10),(1,1,'Apple',10),
(2,0,'Brick',10),(3,1,'Brick',10),
(4,0,'Car',10),(5,1,'Car',10),
(6,0,'Door',10),(7,1,'Door',10),
(8,0,'Echo',10),(9,1,'Echo',10),
(10,0,'Frame',10),(11,1,'Frame',10);

CREATE TABLE revision_userindex
(`rev_id`         int(8) unsigned,
 `rev_page`       int(8) unsigned,
 `rev_text_id`    int, 
 `rev_comment`    varchar(44), 
 `rev_user`       int, 
 `rev_user_text`  varchar(255), 
 `rev_timestamp`  varchar(14), 
 `rev_minor_edit` int, 
 `rev_deleted`    int, 
 `rev_len`        int, 
 `rev_parent_id`  int, 
 `rev_sha1`       varchar(31)
);
  
INSERT INTO revision_userindex VALUES 
(10, 0, 0, 'ce', 1, 'Adam', 20130611000000, 0, 0, 78, 0, '6ow'),
(11, 0, 0, 'ce', 1, 'Adam', 20130612000000, 0, 0, 78, 0, '6ow'),
(12, 0, 0, 'ce', 1, 'Adam', 20130613000000, 0, 0, 78, 0, '6ow'),
(13, 2, 0, 'ce', 1, 'Adam', 20130613003600, 0, 0, 78, 0, '6ow'),
(14, 2, 0, 'ce', 1, 'Adam', 20130613007200, 0, 0, 78, 0, '6ow'),
(15, 2, 0, 'ce', 1, 'Adam', 20130613010800, 0, 0, 78, 0, '6ow'),
(16, 2, 0, 'ce', 1, 'Adam', 20130614030000, 0, 0, 78, 0, '6ow'),
(17, 4, 0, 'ce', 1, 'Adam', 20130614033001, 0, 0, 78, 0, '6ow'),
(18, 4, 0, 'ce', 1, 'Adam', 20130614036001, 0, 0, 78, 0, '6ow'),
(19, 4, 0, 'ce', 1, 'Adam', 20130614039001, 0, 0, 78, 0, '6ow'),
(20, 6, 0, 'ce', 1, 'Adam', 20130614040000, 0, 0, 78, 0, '6ow'),
(21, 6, 0, 'ce', 1, 'Adam', 20130616060001, 0, 0, 78, 0, '6ow'),
(22, 6, 0, 'ce', 1, 'Adam', 20130616061000, 0, 0, 78, 0, '6ow'),
(23, 8, 0, 'ce', 1, 'Adam', 20130616062000, 0, 0, 78, 0, '6ow'),
(22, 0, 0, 'ce', 2, 'Beth', 20130713000000, 0, 0, 78, 0, '6ow'),
(23, 0, 0, 'ce', 2, 'Beth', 20130713003600, 0, 0, 78, 0, '6ow'),
(24, 0, 0, 'ce', 2, 'Beth', 20130713007200, 0, 0, 78, 0, '6ow'),
(25, 0, 0, 'ce', 2, 'Beth', 20130713010800, 0, 0, 78, 0, '6ow'),
(26, 2, 0, 'ce', 2, 'Beth', 20130714030000, 0, 0, 78, 0, '6ow'),
(27, 2, 0, 'ce', 2, 'Beth', 20130714033001, 0, 0, 78, 0, '6ow'),
(28, 2, 0, 'ce', 2, 'Beth', 20130714036001, 0, 0, 78, 0, '6ow'),
(29, 2, 0, 'ce', 2, 'Beth', 20130714039001, 0, 0, 78, 0, '6ow'),
(30, 4, 0, 'ce', 3, 'Cory', 20130814040000, 0, 0, 78, 0, '6ow'),
(31, 4, 0, 'ce', 3, 'Cory', 20130816060001, 0, 0, 78, 0, '6ow'),
(32, 4, 0, 'ce', 3, 'Cory', 20130816061000, 0, 0, 78, 0, '6ow'),
(33, 4, 0, 'ce', 3, 'Cory', 20130816062000, 0, 0, 78, 0, '6ow'),
(34, 6, 0, 'ce', 3, 'Cory', 20130813007200, 0, 0, 78, 0, '6ow'),
(35, 6, 0, 'ce', 3, 'Cory', 20130813010800, 0, 0, 78, 0, '6ow'),
(36, 6, 0, 'ce', 3, 'Cory', 20130814030000, 0, 0, 78, 0, '6ow'),
(37, 6, 0, 'ce', 3, 'Cory', 20130814033001, 0, 0, 78, 0, '6ow'),
(38, 6, 0, 'ce', 3, 'Cory', 20130814036001, 0, 0, 78, 0, '6ow'),
(39, 6, 0, 'ce', 4, 'Dirk', 20130814039001, 0, 0, 78, 0, '6ow'),
(40, 6, 0, 'ce', 4, 'Dirk', 20130814040000, 0, 0, 78, 0, '6ow'),
(41, 6, 0, 'ce', 4, 'Dirk', 20130816060001, 0, 0, 78, 0, '6ow'),
(42, 6, 0, 'ce', 4, 'Dirk', 20130816061000, 0, 0, 78, 0, '6ow'),
(43, 6, 0, 'ce', 4, 'Dirk', 20130816062000, 0, 0, 78, 0, '6ow'),
(44, 6, 0, 'ce', 4, 'Dirk', 20130814063000, 0, 0, 78, 0, '6ow'),
(45, 6, 0, 'ce', 4, 'Dirk', 20130816064001, 0, 0, 78, 0, '6ow'),
(46, 6, 0, 'ce', 4, 'Dirk', 20130816065005, 0, 0, 78, 0, '6ow'),
(47, 6, 0, 'ce', 4, 'Dirk', 20130816066010, 0, 0, 78, 0, '6ow'),
(48, 6, 0, 'ce', 4, 'Dirk', 20130816066015, 0, 0, 78, 0, '6ow'),
(52, 2, 0, 'ce', 2, 'Beth', 20130713000000, 0, 0, 78, 0, '6ow'),
(53, 2, 0, 'ce', 2, 'Beth', 20130713003600, 0, 0, 78, 0, '6ow'),
(54, 2, 0, 'ce', 2, 'Beth', 20130713007200, 0, 0, 78, 0, '6ow'),
(55, 6, 0, 'ce', 2, 'Beth', 20130713010800, 0, 0, 78, 0, '6ow'),
(56, 6, 0, 'ce', 2, 'Beth', 20130714030000, 0, 0, 78, 0, '6ow'),
(57, 6, 0, 'ce', 2, 'Beth', 20130714033001, 0, 0, 78, 0, '6ow'),
(58, 6, 0, 'ce', 2, 'Beth', 20130714036001, 0, 0, 78, 0, '6ow'),
(59, 6, 0, 'ce', 2, 'Beth', 20130714039001, 0, 0, 78, 0, '6ow'),
(60, 6, 0, 'ce', 2, 'Beth', 20130714039001, 0, 0, 78, 0, '6ow');

readme.txt

Finding closely affiliated friends. 
These queiries are built to operate on a small datasets at http://sqlfiddle.com/#!2/907b6/1. 
For work on a real wiki numbers in these queries will require fine tuning.