Like "censorship" and "privacy", it's best to finally produce a concrete definition that we can use as a yardstick to tell whether or not someone is doing something unethical. Let's clearly lay down the criterion for what constitutes "unethical patching" so we can recognize it when we see it.
- unethical patching
- a message from a sender to a receiver is modified by the receiver in accordance with a message from a third party in such a way that the human-experienced message automatically depends on the third-party message (as "dependence" is defined previously), without the consent of both the sender and the receiver, then the act of modifying the message is unethical patching.
This definition is actually quite elegant, because of the way it is based on the earlier definition of "depends". If there is no change at all to the human-experienced message, then there is no patch, whatever technical stuff may have been going on behind the scene. (Translation: It is actually OK to use an annotation service if you go to a webpage that has no annotations. Pointless, but ethical.) If the change is "independent", then there is no problem. (Translation: It's even OK for the annotation service to provide a console on the screen for controlling the service, as long as it is independent of the web page; the ones I've seen are.) Once the human-experienced message changes in a way that depends on the third-party content, the line has been crossed. The simplicity of the definition is the source of it's power; something so simple can not be danced around by hiding in a corner; either there are concrete parts intruding from a third party or there are not. This is an advantage held by this definition over every other ad-hoc attempt to justify annotation, but not changing the web page... or changing the web page by adding Smart Tags, but not changing the actual "words"... or justifying ClearPlay while standing against other things in this chapter... or even trying to justify all of these things while still pretending that the result isn't simple anarchy, with the corresponding loss of free speech.
There are things that this definition explicitly does not cover. Note that "unethical patching" includes the concept of "dependence", so things that are independent of the message are still OK. For example, there are several toolbars you can download that will allow you to easily get a list of web page that link to the one you are currently reading. These links are independent of the message, so adding this information in an independent way would not constitute unethical patching. Such functionality is not "unethical patching".
The line starts to get fuzzy here; consider web pages. Alexa's tool bar shows the links in what is clearly a separate window not belonging to a web page. crit.org, in addition to providing annotation services also provides a back-link service, but puts the information in the web page itself (which it can do because it functions as a proxy server). (As of this writing, it seems crit.org may have been unplugged.) So it's possible that even the same information in different places could affect how the original message is perceived and thus violate the independence of the original message. I personally would draw the line between Alexa and crit.org, saying that the information should not appear to belong on the web page, but I think it's much more important to understand that dependent content is bad then argue about exactly where independent content should go to make it clear it's independent, which will be strongly medium-dependent and even message-dependent anyhow.
The implied definition of "independent content" here would be "content that it is at least possible to present in a fashion preserving the independence of the original message". Backlinks can be shown in an independent manner; annotations can not, because by their very nature they depend on the annotation target for context.
Also note the word automatically. It's a critical word in the definition. Suppose you are running a advertisement-filtering web proxy and a friend emails you and comments that www.WeWishWeCouldPutAdvertisementsOnTheInsideOfYourEyelids.com is serving a lot of ads. You can still manually add that domain to your blocking list, because there's nothing "automatic" about that addition. "Automatic" here means that the control over the results lies not in the hands of the receiver, but in some third party. Adding a single domain to the proxy, and thereby blocking content from that domain, is clearly an action of the proxy owner. On the other extreme, a proxy that automatically downloads updates every hour from some centralized server not under the proxy owner's control is giving the control to that central server owner.
Of course there is no way to easily draw a line that completely delimits how much control is given to a third party and how much is given to the receiver. You could sit all day and spin borderline scenarios... "What if the user has to individually agree to each annotation?" "What if we make the user do something like copy & paste the annotations into the web page?" "What if the user has to type the annotation before viewing it?" While there may be a thin boundary condition, what it boils down to is pretty simple: you can't allow someone else direct access to the message, to change it in any way. The message is between you and the sender. The key is the level of involvement you have with the decision.
Determining who is responsible for the unethical behavior depends on exactly who is doing what; the patcher may doing it against both the will of the sender and the receiver (perhaps it's government censorship), in which case it's the patcher's responsibility. Or the receiver may be doing something with the received message and using information from a third party without the third party's knowledge, such as in the case of framing, in which case it's the receiver's responsibility. The receiver and the third party may be cooperating, like annotation. It is not likely that the author is responsible, since in such cases the activity of the third party would then simply become part of the message; for instance, many large web sites outsource their advertising to a large advertising company, who will add images to the company's pages. However, this is intentionally part of the message the company wishes to send, so that isn't really a "third party". Accepting any third party the author invites essentially becomes one of the conditions of communication. Remember that since everybody is a sender at some point there's nothing asymmetrical about this; when it comes time for the current receiver to send a message they are equally free to impose such conditions.