Nicholas Carr suggests in this article that hyperlinks such as the one in this sentence are a bad idea. He compares links with footnotes, saying that they are similar but more distracting:

The link is, in a way, a technologically advanced form of a footnote. It’s also, distraction-wise, a more violent form of a footnote. Where a footnote gives your brain a gentle nudge, the link gives it a yank. What’s good about a link – its propulsive force – is also what’s bad about it.

While agreeing that we should evaluate links by comparing them with footnotes, I think that the comparison is overall favorable toward links. For example, consider the difference between footnotes and endnotes. Endnotes are certainly less distracting as long as you don’t look at them, since they aren’t there on the page. But if you actually go and read the endnote, they are more distracting than footnotes, since you have to flip to the back of the book or chapter and seek out the note. In fact, there does not appear to be any real reason to use endnotes unless you simply don’t want people to read them, in which case perhaps they should not be included in the first place.

One could make a similar argument against using footnotes, and in fact Stephen Breyer has made this argument.

Sometimes it’s awkward to use none at all, but if in fact you even use one, then you cannot make the point. And it is an important point to make if you believe, as I do, that the major function of an opinion is to explain to the audience of readers why it is that the Court has reached that decision.

It’s not to prove that you’re right: you can’t prove you’re right, there is no such proof. And it’s not to create an authoritative law review on the subject. Others are better doing that than I.

It is to explain as clearly as possible and as simply as possible what the reasons are for reaching this decision. Others can then say those are good reasons or those are bad reasons. If you see the opinion in this way, either a point is sufficiently significant to make, in which case it should be in the text, or it is not, in which case, don’t make it.

This of course relates to court opinions in particular, and we can support footnotes in general by saying that they are intended to give supporting or additional information without forcing the reader to consider it. If this is worth doing, it will be worth paying the price of causing some distraction. Links are perhaps more like this. But they have an advantage over endnotes insofar as they don’t require flipping to the end, and they have an advantage over footnotes insofar as they don’t require looking to the bottom of the page. This assumes of course that the reader is intelligent enough to open his links in separate tabs rather than jumping to another page as soon as he comes upon a link.