How to confront possible theft of ideas? I sent a paper to a fellow PhD student in my department for feedback. In person, he gave me some comments and implied that he had already considered some of the ideas I had suggested. I recently learned that, about one week after our meeting, a blog post was published anonymously containing many of the ideas in my paper. The blog is clearly written by the student to whom I had sent the paper and contains no mention of me.

Part of why I'm concerned is that if I now try to publish these ideas (in a journal, not a blog), I'm afraid that someone will accuse me of stealing the ideas from that blog post (or dissertation or journal article, if the blog post gets developed further). And, in addition to the possibility of being scooped, there is also the possibility of him having stolen my ideas here. So I'm wondering what to do.

On the one hand, he said or at least implied that he had independently come up with these ideas, and I don't yet have any evidence to the contrary. And I suppose this person's behavior may be what you would expect if he did come up with the idea independently before reading my paper—perhaps he's trying to stake a claim to the ideas before I publish the idea myself. On the other hand, it seems to me extremely fishy that the post was published so quickly after I sent him the ideas. And it also seems wrong (even in a blog post) not to at least acknowledge that these ideas have been independently developed by someone else (namely, me).

Should I:


Email this person about it in some polite but non-confrontational
way? (But I won't really be satisfied unless he proves to me that he
came up with the ideas independently, by sending me a draft that was
clearly written before I sent him mine.) 
Tell my or his advisor, or some other faculty member, about the situation and put it in their hands? (But I don't want to seem accusatory.) 
Just ignore it and try to publish the idea as soon as possible?
Do something else?
I found myself in a similar situation once, also with a blog post, though in my case the poster fully admitted posting my ideas and appeared to see nothing wrong with it.  Fortunately, I later determined the specific idea wasn't as fruitful a line of inquiry as I initially imagined and happily moved on.

So, my suggestions to you:


It is fishy, and one clear lesson to learn is to not trust this person with your work in the future.
Hold on to records of your communication, in particular any emails where you discuss this idea and/or send him drafts.  As was pointed out in the comments, blog posts aren't publications, but it's still possible someone notices in the future and asks you about it.  Having the email where you sent your work to the poster for review from before they posted it is a solid defense.
Mention it to your advisor, but I would personally only do it as an aside, as something that annoyed you.  You can handle it!  If they, knowing you and the situation and the work itself, have other suggestions, they'll offer it at this point.
Don't bother bringing it up with that individual.  If they did steal the idea from you, they can just deny it and all you have is circumstantial evidence.  On the other hand, if they had indeed done similar work on their own already, then it seems they posted this in order to get their name on it before you (they can always claim their anonymous blog later), in which case you're competing to get this published.  Therefore,
Take it as motivation to push through and finish your work both well and promptly.


Good luck!