These commands will delete records from the tables field_data_comment_body and field_data_revision_comment_body, so be advised to make a backup first!
DELETE t1.*
FROM field_data_comment_body t1
LEFT JOIN comment t2 ON t1.entity_id = t2.cid
WHERE t2.cid IS NULL
DELETE t1.*
FROM field_revision_comment_body t1
LEFT JOIN comment t2 ON t1.entity_id = t2.cid
WHERE t2.cid IS NULL
OPTIMIZE TABLE `field_data_comment_body` ,
`field_revision_comment_body`
Heise has developed a solution to provide more privacy to users of social networks: http://www.heise.de/ct/artikel/2-Klicks-fuer-mehr-Datenschutz-1333879.html 
To use this script with Drupal, there is the module »Social share privacy«: http://drupal.org/project/socialshareprivacy
The already announced Drupal module is now working for Drupal 7.
The tips on this page can be rated with the fivestar widget. It now happend that more and more entries got a very bad rating. As a result, the list of good rated articles on the front page shortened and became just on entry.