Manage Multiple Projects

I have just got comfortable with using projects. My question is how do you manage multiple projects? I would like to setup a new project for all my new clients. I will assign each client a login and assign them to their particular project. If a client creates a new forum message, how will I know that they have added something to their project?

Let's say I have 20 clients and 20 projects (paid version), I can't sit there and check through each project looking for updates.