Owing to summer-session teaching and a sprained ankle, I have been less attentive to the churn of online happenings than I usually am, but an email from SciCurious brought to my attention a recent controversy about a blogger's "self-plagiarism" of his own earlier writing in his blog posts (and in one of his books).
SciCurious asked for my thoughts on the matter, and what follows is very close to what I emailed her in reply this morning. I should note that these thoughts were composed before I took to the Googles to look for links or to read up on the details of the particular controversy playing out. This means that I've spoken to what I understand as the general lay of the ethical land here, but I have probably not addressed some of the specific details that people elsewhere are discussing.
Here's the broad question: Is it unethical for a blogger to reuse in blog posts material she has published before (including in earlier blog posts)?
A lot of people who write blogs are using them with the clear intention (clear at least to themselves) of developing ideas for "more serious" writing projects -- books, or magazine articles or what have you. I myself am leaning heavily on stuff I've blogged over the past seven-plus years in writing the textbook I'm trying to finish, and plan similarly to draw on old blog posts for at least two other books that are in my head (if I can ever get them out of my head and into book form).
That this is an intended outcome is part of why many blog authors who are lucky enough get paying blogging gigs, especially those of us from academia, fight hard for ownership of what they post and for the explicit right to reuse what they've written.
So, I wouldn't generally judge reuse of what one has written in blog posts as self-plagiarism, nor as unethical. Of course, my book(s) will explicitly acknowledge my blogs as the site-of-first-publication for earlier versions of the arguments I put forward. (My book(s) will also acknowledge the debt I owe to commenters on my posts who have pushed me to think much more carefully about the issues I've posted on.)
That said, if one is writing in a context where one has agreed to a rule that says, in effect, "Everything you write for us must be shiny and brand-new and never published by you before elsewhere in any form," then one is obligated not to recycle what one has written elsewhere. That's what it means to agree to a rule. If you think it's a bad rule, you shouldn't agree to it -- and indeed, perhaps you should mount a reasoned argument as to why it's a bad rule. Agreeing to follow the rule and then not following the rule, however, is unethical.
There are venues (including the Scientific American Blog Network) that are OK with bloggers of long standing brushing off posts from the archives. I've exercised this option more than once, though I usually make an effort to significantly update, expand, or otherwise revise those posts I recycle (if for no other reason than I don't always fully agree with what that earlier time-slice of myself wrote).
This kind of reuse is OK with my corporate master. Does that necessarily make it ethical?
Potentially it would be unethical if it imposed a harm on my readers -- that is, if they (you) were harmed by my reposting those posts of yore. But, I think that would require either that I had some sort of contract (express or implied) with my readers that I only post thoughts I have never posted before, or that my reposts mislead them about what I actually believe at the moment I hit the "publish" button. I don't have such a contract with my readers (at least, I don't think I do), and my revision of the posts I recycle is intended to make sure that they don't mislead readers about what I believe.
Back-linking to the original post is probably good practice (from the point of view of making reuse transparent) ... but I don't always do this.
One reason is that the substantial revisions make the new posts substantially different -- making different claims, coming to different conclusions, offering different reasons. The old post is an ancestor, but it's not the same creature anymore.
Another reason is that some of the original posts I'm recycling are from my ancient Blogspot blog, from whose backend I am locked out after a recent Google update/migration -- and I fear that the blog itself may disappear, which would leave my updated posts with back-links to nowhere. Bloggers tend to view back-links to nowhere as a very bad thing.
The whole question of "self-plagiarism" as an ethical problem is an interesting one, since I think there's a relevant difference between self-plagiarism and ethical reuse.
Plagiarism, after all, is use of someone else's words or ideas (or data, or source-code, etc.) without proper attribution. If you're reusing your own words or ideas (or whatnot), it's not like you're misrepresenting them as your own when they're really someone else's.
There are instances, however, where self-reuse presents gets people rightly exercised. For example, some scientists reuse their own stuff to create the appearance in the scientific literature that they've conducted more experimental studies than they actually have, or that there are more published results supporting their hypotheses than there really are. This kind of artificial multiplication of scientific studies is ethically problematic because it is intended to mislead (and indeed, may succeed in misleading), not because the scientists involved haven't given fair credit to the earlier time-slices of themselves. (A recent editorial for ACS Nano gives a nice discussion of other problematic aspects of "self-plagiarism" within the context of scientific publishing.)
The right ethical diagnosis of the controversy du jour may depend in part on whether journalistic ethics forbid reuse (explicitly or implicitly) -- and if so, on whether (or in what conditions) bloggers count as journalists. At some level, this goes beyond what is spelled out in one's blogging contract and turns also on the relationship between the blogger and the reader. What kind of expectations can the reader have of the blogger? What kind of expectations ought the reader to have of the blogger? To the extent that blogging is a conversation of a sort (especially when commenting is enabled), is it appropriate for that conversation to loop back to territory visited before, or is the blogger obligated always to break new ground?
And, if the readers are harmed when the blogger recycles her own back-catalogue, what exactly is the nature of that harm?