It's hard to put into words! In my region, we would tend to say "John might like this." instead of "This may be of some interest to John." I would think the "interest" saying would be found in a business situation rather than a personal situation. Also, there tends to be (for me) a slight negative connotation with "be of some interest" phrase in my mind. Imagine that you and another person are talking and discover a third person is saying or doing something negative to a colleague or companion of yours. You would say "This may be of interest to [colleague]." There's a bit of secrecy, if you will, associated with the saying "be of interest to" because when someone says that, they are planning to reveal something to the person for whom it may hold interest. I hope that helps.

Sorry. An example. John: How are you today, Peter? Peter: I'm fine. I just had lunch with Cindy. John: Oh? I heard she couldn't leave her house because she was pregnant with an alien baby. Peter: Well! That may certainly be of interest to Cindy! ********** Scott: Hi, Bob. Bob: Hi, Scott. What are you up to? Scott: I was cleaning out my desk and found this old file containing case notes from that big trial a few years back. Bob: Well, hang on to those because Larry is working with that company now and they may be of interest to him.