It is common to label a link as “NSFW” like this:
“And here are my surgery pics (NSFW).”
Here NSFW stands for Not Safe For Work; stuff that you might not want your boss or co-workers to see on your screen. Or stuff that your operation’s IT goblins might flag; or the like. Usually tits, or sensuality of some such sort.
Other such labels are “PDF” (self-explanatory) and “annoying autoplay video grrrrh” (likewise).
Surely this is not enough.
Since four letters is plenty, these brief suggestions for content people might be peeved by are limited to four letters.
CACA — The link might not be to a reliable source of information, or a cogent source of opinion.
DICK — Those on blood pressure medication should not follow this link. Following this link may ruin your day and destroy your faith in humanity.
COCK — A seriously unpleasant person ahead: a misogynist, a racist, etc.; basically a DICK, but even more so.
NUTS — Like the previous, but not even worth arguing with.
CUBE — Time Cube level crazy. If DICK makes you angry, COCK furious, and NUTS throw your hands up in despair, with CUBE there is no space for emotions other than wonder, tinged with fear.
MAIL — Daily Mail, UK’s leading research institute into ethnological causes of cancer.
XIAN — Annoyingly Christian. (Not that, we hasten to add, all Christians are…)
ATHY — Annoyingly atheist. (Not that, we hasten to add, etc. etc.)
X774 — “Really, I find X just as annoying as -X.” (To which the reader might want to answer, “Well, the important thing is that you’ve found a way to feel superior to both.”) (reference)
YHWH — Annoying self-deifier.
PITS — A place where the commentariat will eat you. Some pits have slime, other are quite nice, but a warning about the ferocity is often a good thing.
GITS — The commentariat is equal parts people and dicks, and a new commenter’s fate will be death by a thousand pricks. (Basically, PITS and GITS is a combination you shouldn’t ever click.)
NITS — The commentariat tends to get caught up in details. (PITS and GITS and NITS, your head assplode!)
ZITS — The commentariat’s average age is thirteen. (Often associated with PITS and GITS and the word “bitch”; NITS, not so much.)
KITS — The commentariat has monomaniacal hobby interests. Modulate your commentary and expectations accordingly, and expect there to be some things you just don’t say. (“You have been banned by: UnicronChaser. Sentence: 9000 Years Ban. Reason: UNDERBASE STARSCREAM COULDN’T DEFEAT UNICRON!!!!!!!! STFU!!!”)
WITS — The commentariat is a Mensa Muscle Show; basically, don’t comment unless you can excise all monosyllabics and name-drop at least two relevant academics.
SITS — Because the H didn’t fit; there is a lot of spam / self-promotion / banner ads here.
MITS — You might want to put a pair of mental mitts on, because the commentariat is not sparing with invective. Basically, you’ll be called a child-molester for commenting.
HITS — The site linked to may be Boing-Boinged, Slashdotted, Pharyngulaed, etc. etc., very soon. Make haste!
TITS — Well, what do you think?
WIKI — Wikipedia. Just so you don’t think it will be something more or less.
SINK — A timesink. Don’t follow the link unless you have iron self-control or half a day. (Example: TV Tropes (SINK))
WINK — “This link does not imply endorsement, and frankly I’m insulted you thought it might.”
SQCK — Squick. For an example, er, you can google for “Moomin porn” on your own.
ICKY — Like squick, but less so. (Mind you, to my eye “squick” is a term like “spicy”: some like it, some don’t, but no moral judgment attaches.)
PORN — Rather self-explanatory, isn’t it?
PRON — See previous.
PR0N, PRWN, N0RP, XXX!, BWBS, 3==0, 3->= — See previous; then adjust your expectations downwards.
STFU — “Here is the information you requested with your comment ‘nobody knows the year when LBJ died OMG CONSPIRACY!’, so now shut the fuck up and let us return to useful arguments.”
OMFG — “I just got this in the mail from the lab and look at this link everybody, I now own my full genome!” (What?)
SOCK — “This is momentous, you should follow this link, it will blow your socks off!” (Or “About socks.”, or “This is a picture of me wearing nothing but a sock. Sorry if you misinterpreted the tag.”)
XKCD, SMBC — Good webcomics.