I'm happy to report that the book doesn't simply urge that everyone adopt Gmail and Google Calendar and leave it at that. Instead, the book is a wide survey of competitive solutions and, of most interest to you, how to wire the calendars embedded in such solutions to each other.
Coleman brings years of expertise on groupware, and Levine's published works focus on helping groups work together. Another contributor was Coleman's Collaborative Strategies colleague Ann Marcus, who worked at InfoWorld in the 1990s at the same time I did.
I'm going to limit my review to the portion of the book dealing with calendar sharing. There's a lot of other info on all kinds of messaging, ranging from texting to avatars. I guess my view is calendar interoperability is a particular kind of messaging, structured a particular way, around events (and, increasingly, tasks). In Chapter 5, Coleman nails the problem:
"How many times has it take 12 different e-mails to set up a simple meeting or conference call with three to four people."A few pages later, Coleman describes the ten distinct steps required for the meeting organizer to arrange one meeting. Clearly this has to change. Using a calendar-sharing service such as TimeBridge can cut this process to five steps. It's heartening to see such a calendar-sharing service featured in a book (for the first time?). Then Coleman compares TimeBridge to a U.K.-based service I was unfamiliar with called ikordo. ikordo mainly relies upon email as the final messenger to arrange meetings, which is probably a necessary evil since so many people don't use a calendar no matter what. There's an Outlook plug-in now in beta, plans to support Google Calendar, but no Apple iCal support planned as of yet.
Coleman also gives an overview of Tungle, a "meeting coordinator" Web site I've been aware of for a while but haven't mentioned here on Calendar Swamp.
Another option I wasn't aware of that Coleman dug up was iPolipo -- which since publication of Collaboration 2.0 has been renamed Jiffle. I took a quick look, and it seems to have a sophisticated free/busy service that lets you mark different portions of your calendar free depending on who's asking. I'm sure we're going to see a lot more of this kind of service.
Finally, there's a mention of Calgoo, which I've written about before in these pages.
Overall, kudos to David Coleman for taking the bull by the horns in the first calendar-sharing comparison of its kind. If you're serious about tracking this like I am, check out Collaboration 2.0 and subscribe to Coleman's blog.
UPDATE: Corrected URL for Jiffle. It's www.jifflenow.com.