First of all, the calendar view will change. You will see your own reservations and reservations on devices you have admin access to as before, but other reservations show only time and date, and optional title, if the user has given one. Those reservations will have brown highlight color.
When clicking on a reservation with a brown highlight color, you'll see only time, date and the name of the reserved resource.
The reservation form has been changed a little, too. Reservation title will be replaced by "Optional title (shown to all users)". Filling this field is not mandatory.
Even if the system keeps the identity of other users a secret, you can send them messages. Click the "Send a message to the user" button, and a pop-up window will appear. Your email address will be shown to the recipient, and they may respond to you at their discretion.
The email Infrabooking sends looks like this:
Infrabooking keeps the messages you have sent to other users for 30 days, and deletes them afterwards.