Just now when I tried to subscribe the feed of a blog, I mistakenly copied the url of the RSS and pasted it on a del.icio.us post window (yes I still manually copy the urls and paste them on rss readers & del.icio.us). It was just a mistake but it reminded me that I could combine all the fancy functions of web2.0 applications into only one search bar, which will automatically parse the things I input and pick the best application for that thing. And I should be able to costomize the applications they use. For example, I can setup the social bookmark website I like (del.icio.us), RSS reader I use (zhuaxia), serach engine I favor (Google), flv video downloader (...), and so on. And as I type in any text in the "search bar", it uses google; for urls, it uses del.icio.us; for RSS addresses, it takes zhuaxia (and it can recognize urls from feedburner as RSS). It will be smart.
I love integrating different things and make them a mashup. It is just an idea. I may think about it when my web2.0 project "IC" (keep the name for a secret now) is done.