I am a hacker.
I am also an adult and therefore I actively choose what to do with my time and what to build, and whether to build something cool, useful, both or neither.
What I really don't need is inarticulate people who haven't demonstrated any particular expertise in anything giving me advice on what to build and how I should spend <b>my</b> time and resources.
Now go away and do something useful.
As you said, "Sorry if I offended you .. , don't take it personally."
Why should I spend time on "proving you wrong" or "showing you what I have"?
Who are you to judge what is useful or not, how other people should spend their time and resources? If you are not a hacker that is fine. Just "prove to us" you are good at something (anything!) before making such outlandish requests asking other people to change how they work to satisfy your notions of what is proper.
If a hacker wants to work on a webOS (to use your example) it is no one's business but his own. If you have some inchoate desires on how you'd like the internet to function, and you can't do anything about it and are not willing to pay anyone to do it, its just too bad.
"hey Wall Street Investment Bankers, I don't think you provide any value to me by working on exotic derivatives. I don't understand how they work or why you spend time on them. Please stop what you are doing and work on balancing my bank account and pay my credit card bills for me and persuade my bank to give me more money"
Bozo alert! Other people don't exist to satisfy your desires or work towards your vision of what the world should be. You might be able to get other people to work towards what you want if you offer something in exchange - money, skills etc. In the absence of having anything to exchange, you are just babbling into the wind.
Demanding that someone work in a style that seems perfect to you (when you admittedly know nothing about what they are working on or what the issues are) seems to be .... suboptimal.
If there were big demand for this kind of service, a startup could launch that became MyWebApps.com - a place where your data is stored and which has interfaces to the key other apps that you use and allow data to come out and possibly synchronizes etc. Your portal to the web where you always go first. This is a pretty ambitious idea with countless lines of code involved for getting all the different systems to speak the same language, but if it were pulled off, it could be big.
Regarding the "personal API," I think it's a good idea if properly implemented (read: incredibly easy to use). Obvioulsy you haven't done much research because there are people working on this already. Someone below mentioned OAuth, and OpenID is another effort in this direction.
You'd get a lot farther if you simply just asked the community if someone was working on this and/or pointed out that it's a good, useful idea.
Fear not though, the problem your discussing is probably the trendiest of all trendy ideas anyone is working on right now. It will be solved, by people who can articulate it in terms users can understand and create it.