There are a lot of Web 2.0 tools out there, probably too many right now, but that's all part of the process. The truly exceptional tools to me are those that I really can't imagine (or perhaps even remember) life without. Tripit is one of those tools.
A group of my friends and me all take an annual ski trip together, coming from all over the country and heading off to a different part of the skiable world. We've done Zermatt, Whistler, Tahoe, Telluride, Jackson Hole, Wengen/Interlocken and this season Banff/Lake Louise/Revelstoke. After a litany of email conversations only Google could sort through, I had to tip my crew onto the wonders of TripIt. A lot of them are locked in the banking world and don't exactly jump at the latest Web 2.0 tools, so it took a little pushing on my end. After all of us had easily loaded our many flights, SUV rentals, CAT skiing reservations, etc. up to the site, we had a clean, interactive shared group itinerary.
During the trip if we ever needed someone's flight arrival or hotel address, an iPhone would pop out and someone would say, "Don't worry, I'll just check our Tripit." This was a tipping point in my group. It made me smile.
For someone who travels a lot, I've found it invaluable in keeping it all together. The seamless ability to forward any airline ticket confirmation email to "email@example.com" and find it all loaded up into my calendar is priceless. I then subscribe in iCal to my Tripit calendar and I get a real-time updated travel calendar all by forwarding one email. Wow.
The company is backed by a $1 million seed round (in April 2007) from O'Reilly AlphaTech Ventures (OATV), though it feels like there must be some additional backing. If not, it's one of the best uses of $1 million I've seen in a while.