HTML Forms: Capturing User Input

Old Techniques
On of the most frustrating thing to do on the web today is to fill out forms. How many times do you have to enter your address or phone number? Most web developers don't really think about this too much. They create and HTML form for the data they need. Some add in some JavaScript to make it a little easier to fill out. Some break up the form into smaller parts or suggest certain input based on already entered data. Others take advantage of location based technology to help fill out forms. The bottom line is there has to be an easier way to do this. There have always been form auto complete add on as long as I can remember but they don't always work. First you have to be on the same computer that you set up the auto complete on. What if more than 1 person uses that computer? What if you don't want that information available to anyone that uses your computer?
New Techniques
Some of the new solutions try and address all of these issues. One really cool technology allows you to sign in with some kind of social network account and that website will pull information via APIs from your profile. This will autocomplete a lot of stuff for you and make your life much easier. You don't have to worry about being on a different computer because everything is stored in the cloud. There are some security concerns with this process. Once you log in can you control how much information this new website has access to? Do you want them to have your cell phone number or just your home phone or maybe no phone. Which email address do you want to give them? This might sound like a good idea at first but there are a lot of other issues that arise.
Random Idea
What if there was a way to log in to a site and create a profile of your contact information. Name, address, phone numbers, etc. Then when you come across another site that has a form just log in to the original site and then pick a profile or drag and drop certain items onto the form of the new site.