If you travel much, this is one web-app I think you will find useful. Simply forward your booking email confirmation (from any provider) to plans@tripit.com and let TripIt take things from there. The system, which is free to use, will then automatically scour your itinerary for information and then build a portfolio of useful information for you. Once you have your itinerary sent over, simply access all your information through the website m.tripit.com. TripIt pulls information from many sources such as Google, NOAA, SeatGuru, Wikipedia, Eventful, Flickr, and OpenTable. Pretty cool stuff. From TripIt:
TripIt turns chaos into order by making it easy for anyone to: -Organize trip details into one master online itinerary — even if arrangements are booked at multiple travel sites -Automatically include maps, directions and weather in their master itinerary -Have the option to book restaurants, theatre tickets, activities and more right from within the online itinerary -Safely access travel plans online, share them, check-in for flights, or print an itinerary
Popularity: 54% [?]
I started using the Google Notebook plugin for Firefox when it was launched some time ago. It is really useful for grabbing little notes from sites as you wander the internet (or World Wide Web, for those of you still on CompuServe.) I found the limitation to Google Notebook was that you had to be at your computer to use it. This has been solved with the mobile version.