Blocked Websites

I'm not sure if I have malware or a virus or it's just the diligence of F-Secure.

Recently I have been unable to view videos at some tube sites because it's being blocked by F-Secure reporting that "Harmful web site blocked". The websites are (among others):
- http://syndication.exoclick.com/ads-iframe-display.php (most popular)
- http://a1.elekted.com/yjizzone.php
- http://adbucks.brandreachsys.com/www/delivery/afr.php

The interesting thing is that the video (audio only) still plays behind the F-Secure warning page. This makes me think there's no redirection, but something on the webpage.

Has this been observed before?

I'm running Windows 7 on an Inspiron 545.

 

That's good to know.

It seems to me, then, that there's something bad on the webpage that F-Secure is blocking rather than me having a redirection or other problem. Would you agree?

I Googled the reported websites, but didn't find much, except some possible references to malware. Do you know where I can find more information that explains what makes them unsavoury?