A short digression: How to say "off topic" in Spanish

At Switch Off and Go, "La navaja en el ojo" writes about the options in Spanish for translating "off topic."

She points out that unfortunately the English term will probably prevail over digresión or any other option in Spanish. The foreign phrase being restricted to the world of blogs and forums, its use signals that the writer is making reference to that sphere. She adds that "off topic" covers all the different facets of off topicness... material that has nothing to do with the blog or site in question; material that does have something to do with it, but not with the current entry; and digressions from the main topic. The meaning of "digresión," in contrast, really only corresponds to the last.

Update: The drama surrounding the release of Harry Potter and the Deathly Hallows reminded me that I had long wondered about spoiler, too. Same story: I am informed that in Spanish they also use "spoiler."