artesea

Whereas the built in moderation just looks for keywords wherever they appear in the comments, Better Moderation allows you to define if it should just be the username, url, email, comment, ip, useragent or all of them. 
It also allows you to define if when looking for “word” whether you should match “WordPress”. 
Finally it lets you set reasons why words have been added to the list, allowing you to quickly realise why a comment has been added to the moderation queue.

Better Moderation

Provides more control over comment moderation

zingming

Hide unwanted comments without deleting them. Edit the comment and wrap the offending text in [shush][/shush]. Example: [shush]FIRST!!![/shush] or [shush reason=”Boring”]FIRST!!![/shush]
Readers can choose to read the buried comment by clicking on the “Show” link.
(Bonus: You can also use this shortcode in your posts as a “Spoiler” hider.)

ShushThatNoise – Ignorant Comment Hider

Hide unwanted comments without deleting them. Readers can click on the "Show" link to read the buried comment.

Better Moderation vs ShushThatNoise – Ignorant Comment Hider