If you have been using WordPress for any length of time you will know that comment spam is a very real problem. Not only does it bring down your user experience, it can hurt your SEO as well if your posts become home to hundreds of spammy links from dodgy websites.
It doesn't have to be onerous to deal with comment spam, but you do need to deal with it. Letting it build up is not an option if you want to run a successful site. You can moderate each and every comment you get, but if your site does become very popular then you can expect to spend a lot of time moderating. Thankfully, there are WordPress plugins that can help you with that.
Akismet is undoubtedly the most popular spam prevention plugin for WordPress. Unsurprising given it is made by the company behind WordPress, Automattic. With more than 13 million downloads and an average rating of 4 stars you know it is good.
Akismet is an intelligent way to fight comment spam on your WordPress blog. It monitors each trackback, pingback and comment your site receives and tests these to make sure that they are not spam. If it suspects that a comment is spam, you would need to approve it before it goes live on your site.
Akismet relies on the input of its many users as well as more than seven years of work to make its spam protection the best there is. What's more, it gets smarter by learning about the new tricks and methods that spammers use.
The plugin needs an API key to work, which is available for free for personal blogs, but if you run a business blog or commercial site on WordPress then you need a subscription starting at $5/mth.
Now $5 per month per site isn't a huge amount, but there are some free alternatives that are definitely worth looking at…
Developed by Sergej Muller and with more than 368,000 downloads to date, Antispam Bee has been in active development since it was launched in 2009. Like Akismet, it employs sophisticated techniques to analyze comments, trackbacks and pingbacks on your site, allowing you to have a spam-free blog. Unlike Akisment, however, it does not store your personal data on site and everything is anonymous. Antispam Bee also notifies as new spam comes in.
What's more, it is free for everyone.
Defensio, created by Websense, Inc., pretty much follows how Akismet does things. It sends new comments, trackbacks and pings to their server and these get analyzed for spam content. But more than just a spam blocker, it also detects malicious content, filters profanity, detects scripts and supports detailed statistics and OpenID authorization.
Defensio is available for free if you have less than 25,000 server calls per month. More than that and you have a choice from three paid plans that start at $299 per year up to $7,999 a year(!!)…25,000 calls per month for free however is a decent number so for most small site owners this is accessible.
These are among the highest rated alternative plugins to Akismet that go beyond just spam filtering and using CAPTCHAs. As with any plugin choice, be sure to choose one that fits your budget, perhaps starting with a free alternative and upgrading to a paid service when the time comes. Each of these would be a good choice and will generally provide very low false positives and will help you manage comment spam on your site.