You've no doubt seen it before: those wonderful four letters that alert us that a certain link should be treated differently than all others around it. Depending on the person, one may either anticipate with glee akin to that of eating from a forbidden tree, or avoid it with the same anxiety as one might avoid a rabid animal. Yes, NSFW is one of the more useful acronyms to have been developed by the collective patrons of the Internet.
All the same, however, one does occasionally fail to notice these instructive glyphs, resulting in shock, amusement and pain. If only there was a way to flag these links at the metadata level so that the browser wouldn't allow you to follow them inadvertently. Luckily for us, the rel attribute of the a element in (X)HTML is designed for such things. If we simply mark links as being NSFW by adding the attribute rel="nsfw" to the anchor tags, then it would become possible to create a Greasemonkey User Script to prevent such links from being followed. This measure would be easily deactivated, thus making it a conscious decision to follow NSFW links. In fact, I am working on just such a script right now. Hopefully I'll finish it soon. If so, I'll post it to this space when I do. In any case, please consider marking your NSFW links with this attribute, and perhaps it will catch on.