After about 130 genuine comments (of which two ended in the spam filter) and about 30 spam comments (of which two passed the spam filter), I can proclaim that the spam filter works! This is as well proof that others who protect their comment section with login and/or CAPTCHA are posers (or have important reasons I don't know; I find it annoying).
Here an extract of what the spam filter caught (with comments in italic):
(The following are an interesting examples of use of non-Latin letters that look like Latin letters, I don't know if there is any purpose other than catching the reader's eye and making it unreadable for a computer.)
Update 13.06.2014 This one is cute:
Today, while I was at work, my sister stole my apple ipad and tested to see if it can survive a 30 foot drop, just so she can be a youtube sensation. My apple ipad is now destroyed and she has 83 views. I know this is completely off topic but I had to share it with someone! Also visit my website: currency exchange rates