Fairly frequently, the contact form on my blog gets comments that look similar to this (each field represents a text box users can enter into the HTML form on the blog):
vaB5LN <a href="http://pepddqfgpcwe.com/">pepddqfgpcwe</a>, [url=http://hvyhfrijavkm.com/]hvyhfrijavkm[/url], [link=http://cwiolknjxdry.com/]cwiolknjxdry[/link], http://ubcxqsgqwtza.com/
I'd consider them to be spam, but the sites they link to don't exist, so they aren't helping SEO or spreading malicious links. Not even the email host,
avbhdu.com, exists. What is the purpose of these comments?