Windows: You probably don't send the same exact resume for every single job opening, and keeping track of what you sent can be a confusing pain. ResumeTracker does a smart job of organizing and labeling your multi-versioned resumes for later reference.
The app itself is still in its early stages, and there are two things to note right off the bat—the app really requires Microsoft Word, unless your non-Word editing tool happens to agree with it, and the app also requires Administrator access to run well. Those complaints aside, ResumeTracker works just fine for the average Windows and Word user, providing an organized way of creating a Master Resume, creating new entries for each job or job title, then linking a customized version of that master resume to each job pitch, with notes on when you sent it, who it was sent to, and the like.
ResumeTracker is a free download for Windows systems only. You'll find it here.