When you do so, use important Keywords that you believe the company is looking for, based on your knowledge of skills they may be looking for. (More and more companies are using scanners to separate potentially interesting resumes from ones that don't fit their needs, so this is important. -- and not just the big companies, by the way. Scanning can be done by a clerk with no particular HR skills, so don't assume this is only important if you are sending your resume to a large company).