Recently one of my friends told me that there is distinct difference between 'know of something' and 'know about something' expressions. 'know of' is used when you have personal experience with wha... "Know about" vs.

Understanding the Context

"know of" - English Language & Usage Stack Exchange Possible duplicate of "Know about" vs. "know of". Also What are the differences between “know”, “know about”, and “know of”? on English Language Learners, which is probably a better site for questions like this.

Key Insights

to know vs to know about - English Language & Usage Stack Exchange If you know about a subject, you have studied it or taken an interest in it, and understand part or all of it. Hire someone with experience, someone who knows about real estate. “know of” vs “know about” - English Language & Usage Stack Exchange Know in (1) refers to the clause that comes right before it, so there's no pronoun necessary -- it's essentially a transform of I know it's your job. In (2), however, the object of know is not indicated, as you point out, so something must be provided. Why do you think that He doesn't know him from his schooldays means that he does know him?

Final Thoughts

It would only have that sense if you added something like In fact, he first met him at university.