YouTube videos and commercial ads

Does YouTube have a problem if you upload video clips that show how something is done and is also used to promote a web-based business?

Say you have a video that shows how to install a Super Turbo Mega Widget, and you have a website address showing at the bottom of the screen, or at the end of the video, you do a little bit explaining that you can go to to purchase one of these marvels.

I have seen videos that promoted businesses on YouTube, but then again, I have seen videos that I knew where in violation of YouTube rules also, so just because the videos are there doesn’t mean they will stay up.

Does YouTube have a problem with people using the site to promote a business? The videos are not made to be an outright commercial for the business, but may have a domain name or verbal mention of the business.