We've had videos for about 4 years now - not too many people go to the videos. Much like Peter, since we have live chat on our sites, people find it much easier to go online and chat.
It's like a Knowledgebase in that regard - it's handy to post a URL to the client so they know the KB exists, but very few search the KB's first and then ask a question.
No different than forums I guess - people post rather than doing a search to see if the question has been asked 1000 times before. Not necessarily this post, but I'm sure you know the posts