Weird Al is very conscious of copyright infringement. He seeks permission from every artist he parodies. If he doesn't get the permission, he doesn't do the song. And parody and satire sit slightly apart when it comes to copyright. And I doubt that Coldplay were attempting to spoof Satriani.

In reply to this comment by HadouKen24:
Even if Coldplay did "rip it off," so what?

Creative works are creative even if they borrow from other sources. What makes them creative is how they use those sources. Whether or not you think Coldplay is a very good band or very original, their use of the melody constitutes a new work, a new take on an old idea.

If we were to make this a big deal, we'd have to get rid of Weird Al Yankovic. A whole lot of classical music is right out; they borrowed from each other all the time, riffing on each others' themes. DJ's would be out of work. They practice their craft by remixing and juxtaposing the very recordings done by other musical artists.

Come on, people. Let's not squash what little culture America has.