They probably do what they claim, but such companies make Web of Trust ratings untrustworthy and misleading. They'll give any site a good rating if an owner pays them, whether the site is safe or not. Don't support them.

Web. Owned by Mozilla.

when I started my computer. It was probably caused by malware. I didn't give it a bad rating because it's porn, but because trustworthy sites never use such advertising tactics.

It's used by YouTube to shorten URLs of videos.

Slovenian Mozilla blog.