Sitepoint recent published an article with some tips for dealing with comment spam, here we discuss some of the options…
Spammers have been using blogs to help boost their standings in searche engines by posting massive numbers of comments that include links to their pornography sites, scams and get-rich-quick sites. If your site is linked by a top-ranked site or blog, then Google will often raise your site’s ranking…or at least that’s the thinking of spammers.
Back in January google and a few other engines introduced the (rel="nofollow") tag which is listed in the article, but firstly listed is:
Don’t Ban Specific IP Addresses
We partly agree with this as most spammers will utilise a range of proxies to spoof their IP hence blocking one IP doesn’t really solve anything. They could have mentioned however that it’s always worth blocking persistent spammers in .htaccess or similar, with a regular look at web stats it’s easy to notice static abusive hosts, whether it’s an inconfigured cache server repeatedly leeching your site or a potential spammers it still needs to be blocked.
The CAPTCHA TEST ( Completely Automated Public Turing Test to Tell Computers and Humans Apart)
"It involves adding to your site’s comments area an image that contains a random piece of text. The text must be somewhat tarnished or blurred so that a human can read it, but a computer cannot. The commenter is asked to copy this text exactly into a form field before they submit the form.
This process makes it easy to guarantee that the commenter is a person, not a bot. It does not solve the problem of a human being spamming your comments section manually. However, as most spamming is carried out automatically by bots, this technique should stop most comment spam."
Captcha is a great step to take but note the final words here, ‘most’ spam. I’ve used captcha before and spammers have still managed to get around it somehow, but its a very good preventative step for stopping automated bots.
I was suprised they didn’t mention the many popular plugins for popular software such as MT blacklist and so forth, even if just the top plugin for each CMS / blog software was briefly mentioned.
A few other methods are discussed including authentication, the full article is available here [Sitepoint.com - Ajit Monteiro ]
Blog spamming and similar has forced some users to disable comments altogether, obviously manual approval of comments is the best method for allowing nothing to slip through but adds an additional delay with comments plus requires time.
We currently manually approve comments here, it would be ironic as a spam site if our site was covered in comment spam (Spam Bully news take note, by showing the last referrers openly on your website you are giving backlinks to referreral spammers, we did notify them about this but they chose to ignore us and aid the spammers.)
No tags