In recent years, orchestra and concert-hall websites have been infected with a virus called What's On. This is a style of divulging concert information that avoids the traditional calendar format and instead presents a horizontal or vertical dribble of events day by day. It works well enough if you are looking at the next few days of programming — the template seems designed for people on mobile phones who want to know what the New York Philharmonic is playing tomorrow night — but when you try to skip ahead a month or two you may find yourself slogging through week after week of listings before being kicked back to your point of departure. For example, if you want to look at April events on the Elbphilharmonie website, you must first click on "What's On," then click on the current month, then click the arrow for April, then click on a particular date to see what's happening. The website for the new Boulez Saal does offer a calendar option, but it works badly. You click on Concerts, then on Calendar View, then advance to April. Yet when you look at a particular event and then try to return to the calendar, you lose your place and lapse back into early March. You must click on Calendar View again, move to April again, etc. This is intensely annoying. Why is it so difficult for organizations to put a clean, legible calendar on the main page? The LA Phil website is a model of clarity. I click on Calendar, I hit the arrow for April, and all the info is right in front of me. Or I can click on Full Season Schedule and see every work, composer, and performer on offer — a feature that can be maddeningly difficult to find on other websites. (As it was in 2005.) Carnegie Hall is also fairly easy to navigate. Lincoln Center, on the other hand, is a stupefying mess. At the moment, their Calendar option causes my browser to crash.