I'm using ASP.NET MVC and creating a public website. I need to keep track of users that are online. I see that the standard way in asp.net of doing this is to keep track of LastActivityDate. My question is when should I update this?
If I update it every time the users clicks somewhere, I will feel a performance draw back. However if I do not do that, people that only surf around will be listed as offline.
What is the best way to do this in asp.net MVC?
Just put an ajax javascript call at the bottom of your master page to track this.
Don't worry about performance at this time. If it's implemented and you see it being a problem then come back to finding a better solution. Something so simple shouldn't be a performance problem.
Just think about it like Google analytics. It sits at the bottom of millions of pages with little to no impact on the user experiences of those sites.