Two WordPress Plugins Which Prevent Spam Comments

Spam is one among the things from which every blog owner wants to keep his blog away. Spammy comments can be annoying. Spam is of two types, One being a user and another being a bot. If a user repeats useless spam comments with links again and again, he/she is regarded as a spammer. A bot-spammer is a programmed script that does all of the spamming many times faster than a human being can do.
Many users adopt Captchas to prevent spam but it some times prevents legitimate users from commenting when the Captcha code breaks off.
Fortunately there are some plugins for WordPress users which regulate spam to a large extent. We are going to discuss about the popular ones i.e., Growmap Anti Spam Bot Plugin and Akismet. Growmap Anti Spam Bot Plugin prevents bot-spammers while Akismet prevents user-spammer.
Working of GASP
GASP works by adding a check box that a commenter has to check before the comment can be submitted. Next to the checkbox is a short message “Confirm you are NOT a spammer.”
The checkbox is dynamically generated in such a way that it makes it difficult for spam bots to successfully submit a comment.
There is a hidden email field in GASP which also prevents spam bots.  Naturally, spam bots tend to fill all the fields present. So they also fill the hidden email field.
Working of Akismet
Akismet checks your comments against the Akismet web service to see if they look like spam or not and lets you review the spam it catches under your blog’s “Comments” admin screen.

Akismet requires a key to work which can be purchased at the main site. Keys are free for personal blogs.
Do you know any other plugins which deal with spam more effectively? If yes, please let me know via the comment form.