This guideline won't apply to every situation, but for most online videos, length should be kept down between 60 and 90 seconds. After all, 20% of people exit a video within 10 seconds if it does not promptly engage them. Adding a lot of time to this only increases the chances they will close the page.
The definitive goal of video marketing is to bring in new business, but it is essential to not make this so obvious. People are not going to be considering videos that equate to nothing more than several minutes of an advertisement. They want valuable content.
Instead of making a long ad, try to insert the product into useful content. Explain an amazing recipe while showcasing the use of branded pottery. Take a lesson from Google Earth, who made an ad that merely showed how their product brought a family back together. Essentially, find a way to advertise without directly advertising.
While YouTube might be the industry giant for online videos, it doesn't hold a monopoly. You can upload to Dailymotion, Vimeo and even Facebook. Uploading to numerous platforms increases backlinks to the main site and improves the likelihood a video will get seen. And ultimately, this is the actual goal, right?
Online video is certainly one of the most valuable content marketing tools out there. This only remains true, though, if you work with the tool properly. The good thing is, half of this battle is just staying away from mistakes like the aforementioned.