If it doesn't make sense to highlight search keywords that web masters wouldn't do that would they?

Highlighting "salmon" menu entries on web site could make sense for the user who is searching for "salmon", wouldn't it?

But let's be more specific: I run a job board (PostJobFree) and recruiters frequently find resumes on Goolge in queries like this:

http://www.google.com/search?q=intitle%3Aresume+sharepoint+C...

If you open first result - you can see how these keywords are highlighted. I'm pretty sure that this highlighting is a convenient feature for recruiters who want to quickly scan resume.