youtube strategy for long videos

Depends on your strategy. For example I watch/listen to some people talk about current events daily for about an hour on youtube. The beauty of this is that people will listen and watch for 60mins straight if you are delivering quality content. They take "commercial" breaks to throw in some advertising to make more money and fund themselves. Which even sometime I don't skip because there advertisements are good themselves.
Now if lets say the people I listen to started to dividing there program in seperate 10 minute video's I will probably just stop listening/watching them entirely and probably alot of other people as well.

Another way would be if providing a youtube tutorial/webinar series of somekind. It certainly would make sense to create smaller video's and section them off in 3 parts -maybe uploading once a week for 3 weeks, creating a little hype campaign. I would bet this would increase overall views, subscribers, likes, and attention to your channel than by just uploading a single 1hr webinar.

If you've content that really makes sense, I think you'd do good with long videos than short ones. Another important part to consider is presentation aspect of the videos.

Really depends on the video and niche.