Q. I posted my stories on my website at the same time as submitting them to various publications. One of them wants to buy my story, but wishes to have "first publication rights." By putting my stories on the web, have I published them?
A. Yes and no. In seeking first publication rights, an editor has two concerns. First, for commercial reasons, the editor presumably wants to be the first to distribute your story to the periodical market. Second, for legal reasons, the editor wants to be certain that no prior publication owns any conflicting rights in your story. Your publication of your own story on your own website does not raise legal concerns about conflicting ownership rights. However, it may be a closer question as to whether your posting of your story on your website could materially diminish the commercial value of the story to your publisher.
By way of background, as a matter of U.S. copyright law (which is not necessarily dispositive on the meaning of "publication" in a private contract with the periodical), it is not clear whether the display of the story on your website constitutes a publication. Here is the definition of "publication" in Section 101 of the Copyright Act:
the distribution of copies or phonorecords of a work to the public by sale or other transfer of ownership, or by rental, lease, or lending. The offering to distribute copies or phonorecords to a group of persons for purposes of further distribution, public performance, or public display, constitutes publication. A public performance or display of a work does not of itself constitute publication.Thus, while the mere "display" of your story on the website may not constitute publication in the copyright sense of the word, the explicit or implicit authorization of your website visitors to download it, print it out, or redistribute it (e.g., through social media) could be.
Accordingly, to be entirely upfront (and to preserve your editor's goodwill), you may wish to disclose to him/her that you have previously posted the story on your website and that you, of course, assume that is not a problem.
An afterthought and amplification: Should an editor of an ink-on-paper periodical care if your story appeared on your own lightly trafficked personal website? Probably not, particularly if you take down the story when you learn that you have placed it with the periodical. On the other hand, you can readily understand why the editor of a printed periodical (or, perhaps especially, the editor of an online periodical) might care about the previous online posting of an article in a highly trafficked website, where it has already have been accessed by many readers and remains available online for free in competition with the periodical's (hopefully paid) publication of your work.