I use Subscribe to Comments on all my wordpress blogs, even before Tante had askes so nicely for it…
The plugin broke with WP 2.2, if you try to change you subscriptions, you ended up with the following message: “You may not access this page without a valid key.”.
So please all your WordPress users who updated to 2.2 (you really should do this!), get the latest version of Subscribe to Comments here for satisfied readers and subscribers 
Some user don’t see the need to upgrade (“it’s just the third number, no new features” blah blah).
The developer blog mentions some severe security issues here so i recommend upgrading as soon as possible.
Don’t bother using “blog by mail” in WordPress 2.2, it’s broken:
And there went another sunny nice rainy morning…
Why on earth has my ‘post_type’ column on my wp 2.0.x based blog no default value? Ultimate Tag Warrior UTW3-14159265 will break and show no tags.
If anyone else has this problem, add
$typelimitsql = "(post_status = 'publish' OR post_status = 'static')"; // From previous version of utw
in ultimate-tag-warrior-core.php right before the class definition. It’s taken from the previous UTW Version.
Edit:
Upgrading to WP 2.1.x changed the table structure… A little hint would have been nice in the utw changelog.