Google Calendar surpassed MSN Calendar last week and is inching toward Yahoo! Calendar.  The biggest competition for all three: lack of use. For the most part, online calendars today solve problems people don’t have. Of the three, only Google Calendar has seen traffic increasing (from a really small base).

The combined reach of online calendars from AOL, Google, MSN and Yahoo is 3.2%; the combined reach of email services from the same companies is 73.7%.

I use an online calendar for work; it’d be hard to work in a giant company without the ease that online calendars provide. In my personal life, I kinda sorta use Google Calendar, but not really. It’s too much work to put data in there. If data streamed automatically into the calendar, it would be much more compelling.

Think of all the email that you get that has calendarable information:

• Travel itineraries, including flight reservations, hotel information and car rentals.
• Bills from credit card companies and utilities.
• Evites and other invitations.
• Restaurant reservations from OpenTable.
• Ticketing confirmations for events.

These notifications are machine generated. Computers should do the work of processing and summarizing this information for us.

There has been a little bit of progress along these lines. Google has done the most among the calendar services to provide automation.

I booked a trip on Northwest and there was an option to save the information to my Google Calendar. It entered detailed information in my calendar including confirmation number, flight number and times, seat assignments – even links to check in online and change my reservation.  Unfortunately, some of the flights had bungled times. Others didn’t appear at all.

GMail also tries to guess at events that might appear in your email and suggest events to add to your calendar. It’s hit and miss; mostly miss in my use. A flight that departs on Feb 1 at 10:10 p.m. gets suggested to appear on my calendar on Feb 2 at 6:06 a.m. (Which is actually the arrival time.) To be fair, trying to make sense of unstructured data is extremely hard.

The event data needs to be sent in a standard format to be truly useful in a calendar context. Ideally, the events would be identified so that they could be automatically updated in case of changes – for example, if the flight schedule changes.