Seriously. Write your own statements, essays, etc. Do this for several reasons. First, maybe you'll actually reveal yourself, and someone in admissions will be sharp enough to realize you'd be a great addition for their campus.
Second, if you really express yourself, maybe you won't sound exactly like a million other self-absorbed high school seniors. No one begrudges you the self-absorption. That just comes with the stage you're in. But please, at least be an original.
Finally, as the Washington Post points out here, schools are using technology to check for plagiarism.
iParadigms was launched in 1996, when researchers at the University of California at Berkeley created a series of computer programs to monitor the recycling of research papers in their large undergraduate classes.Now I don't claim to follow the math there, but the point is woth noting, even if it's poorly illustrated. It's easy to get caught, and that's sure to spike your application.
The admissions technology was used in a study that checked nearly 453,000 personal statements from the 2006-07 admissions season against sources on the Web and found the following:
There were 1,033,813 matches detected in 199,963 personal statements.