Ok, I have a question regarding professional courtesy in Academia. When I was in grad school, I was very close with another person in the same program, who shall be called X. We were roommates for a few years, we shared similar interests, etc. We had a fallen out in my last year, an episode that hurt me a lot, but that it's not what I want to talk about. Our relationship became cold, polite and distant. After I graduated (she did it a year later), I sent her an email around six month after I had moved to my new job, and she replied politely and ending up with something like: "I'm sure we'll run into each other at some conference". We probably trade emails twice a year, mostly for professional reasons.
Last year, in the course of my research for a project, I came upon a book by a not very well not author (except for those with a very specialized sub-field). I loved the novel, but I knew it didn't fit in my project and I wouldn't do anything with it, professionally. However, I also realized it fit perfectly on X research, and that she didn't know its existence. So I emailed her, telling her about the book, and how I thought she might find it useful in her research. She wrote back an email of the sort of : "Thank you very much for sharing the book, I'll take a look at it, have a good day". That was it.
Just by complete chance, I recently discovered that she just finished an article on the book and sent it to a journal for publication. Now, to make it clear: I only made her aware of the existence of the book. I didn't suggest ideas, approaches, criticism, anything. However, I'm a little offended that she did not have the courtesy to at least send me a brief email thanking me for the suggestion and informing me that it had been fruitful, since she had written an article about it. Am I being overly sensitive? Or am I just expecting the correct amount of professional courtesy?