Startup Idea: Graduate School Work Organization Software

Startup idea to create a software for graduate students that organizes their schoolwork by keywords. It would let students attach keywords to assignments, research papers, bills, emails etc and retrieve them through a keyword search.

I am a graduate student at branch of University of California. School work organization is a pain for me and most people. Most college level school work (at least in technical fields) is done on the computer, not with paper and pencil. Keeping organized class assignments, research papers, school-related bills such as rent/housing, emails, and more is difficult because it is left up to each person to create a filing system within his/her own computer.

Software that I would need is something that organizes such assignments by attaching key-words to them. Then using some type of key word search (Fall 2012 Biology, or Probability Theory Homework), it would bring up the relevant files.