Are these services available from your web hosting company? There are multiple ways to do this. One way is to log views of a unique file. Another is to include an ID string in the URL given to the customer. With a little PHP (or whatever you like to work with) on the server side, you can log the views. Unless you have some sort of exit link that the customer must use to stop the view, you’ll have a tough time logging the viewing time. It may be possible to deduce this from some sort of Analytics, but this assumes that the customer leaves the viewing by going to a site that gives you access to time stamp data. For. Example, if the user was observed to load a follow-on site two minutes after starting to view your content, you might deduce that the customer viewed your stuff for two minutes. However, this would not work very well to track me because I’ll have most trackers blocked and I work with multiple open tabs on multiple browsers, on sites that are not likely to be included in someone’s Analytics tracker. And, I might put you on Pause and come back a few hours later.

A similar approach would be to send the user to a custom web page (unique to that customer) that includes a “web beacon”. This is a single pixel image in the background. The image has a unique URL. Your web host might provide beacon tracking services.

If you go deeper into browser scripting there are “onload” and “onunload” events that can be tracked. Again, the onunload event might not be useful for tracking me.

Tracking IP addresses would not work well for tracking me because I get around. Certainly, you might be able to eventually figure out that I spend time at work and at home, but there are multiple users at each location. I could easily be at a customer site or out somewhere using my phone hotspot.