I've been using Tripit for a few months and it's made collecting all the details of my business and pleasure trips as simple as forwarding an email message. The problem with booking your own plans is that as you make reservations online, the number of emails you have to collect and keep track of grows linearly with the number of reservations. Of course, using Gmail to tag those emails in one place and get them out of your inbox works great for personal organization but sharing those plans with spouses or travel companions is difficult. That's where Tripit comes in. You forward all of those emails to Tripit and it parses them, collects them, adds data from other sites like Flickr, weather.com, Google Maps, etc., and combines it all into a useful online itinerary that you can share with anyone. As you plans increase in complexity Tripit becomes more useful because it gives you one chronological web page where you can add notes, more plans, and photos. I'm impressed with the service and it's quickly replacing Dopplr as the site I use to track my travel plans. Why because Tripit takes my data and beyond allowing me to share it, Tripit adds value to the data. e.g. I no longer have to lookup the weather for my destination because Tripit automatically adds the forecast data for every day of my trip right there with my travel plans. It seems trivial but with this approach they could pull data from any web service for my location and give me city guides, photos, travel hints, news, etc. This is the kind of added value I want from a service. Granted I have more friends on Dopplr but considering the personal utility that I get out of Tripit. I think more people might see there way over to Tripit. One downside to Tripit is that unlike Dopplr, they don't have a Facebook app. I don't share trips with just anyone but my Facebook friends might want to see where I'm headed. So for now I'm doing a bit of double entry. So while Dopplr might help me find friends when traveling to certain destinations, Tripit has some features that travelers can leverage to make travel easier and over time will replace Dopplr if the folks there don't play a bit of catch up. I for one am interested to see how competition shapes this space.