Why does this abbreviation "tl;dr" have a punctuation mark in it?

The abbreviated form of "Too long; didn't read" is tl;dr. To me it kind of defeats the purpose of typing an abbreviation quickly, if I have to type the ; key too.

Why is tl;dr more common than TLDR, and usually used with ";"? I have read the wiki discussion but am not too clear on this.

SNAFU comes to mind as one which could be SN-AFU. Are there any other such abbreviations which have punctuations in them?

In several programming languages ; is required at the end of every statement. Its usually seen at the end of every line but multiple statements can be put on one line separated only by semicolons.

As it originated from a tech literate crowd I suspect the semicolon has been added to separate the two statements

too long;

didn't read

tl;dr - programmers like using semicolons to separate statements

edit - A citation has been requested, I originally made this statement based on personal experience of first encountering it only amongst a technically proficient audience before seeing its usage spread.

Unfortunately being internet slang its a touch difficult to track down a verifiable origin, however.

KnowYourMeme's article on tl;dr states

Unknown Origin

It’s not entirely clear where and when t;dr first began, but the term has been used on Genmay since at least 2003. Example: On June 19th, 2003, gen[m]ay user waptang created the thread tl;dr asking “what does it mean?”

as per this article genmay (General Mayhem) is a spinoff forum from [H]ard|OCP (Hardware Overclockers Comparison Page).

Overclocking is a reasonably technically involved process, so I'd feel safe calling them a tech literate crowd.

However, essentially this is conjecture on my part.

Commenters on a reddit thread on this subject suggests a different theory

They are two separate clauses of a related nature. It is correct grammar correct to place a semicolon between them if you did not want them to be individual sentences.

but more than that, it shows that the second sentence is a result of the first. "it was too long therefore i didn't read it"

Though I'm still inclined to side with a latter comment stating

Because it is the only semicolon most of us get to use outside of programming.

TL;DR - Because

TL;DR pt 2 - I believe this to be the case however ymmv

Punctuation, even though there are regularities in it, is almost entirely a creature of custom and fashion. There is no answer to a question like this other than "that's how people have started writing it".

I can think of a handful of ideas but have no references.

The phrase "too long; didn't read" actually makes sense with a semi-colon in place of "too long and didn't read." The short, bursty phrase sounds better (and is shorter) as "too long didn't read." Something feels missing; a semi-colon works. (Why that in place of a colon is what I wonder about. "Too long: didn't read." would work just as well.)

Shortening "too long; didn't read" into "tldr" makes sense. My guess is the semi-colon came with because "tldr" was confusable with something else happening at the time or people were not picking up on the abbreviation until the semi-colon was added.

That being said, there is something aesthetically cool about having the semi-colon that distinguishes it from other shortened phrases. I am having trouble thinking of another phrase that does this. "tldr" just looks like a serial number or massive typo. "tl;dr" looks like it means something. Instead of wondering if the author made a mistake, you know it means something and are encouraged to ask what it means.

The time it takes to add the ; is minimal: The key is one away from l. Tech crowds are used to typing semi-colons frequently and it wouldn't be any more difficult for them to type "tl;dr" than it is to type any other five letter word.

Of note, the abbreviate appears to be under quite a bit of meme pressure. The forces of the internet don't seem entirely happy with it yet. I have heard people refer to it as a "tealdeer" or "teal deer" and even spell it out as such. "tldr" is used. Authors as well as readers use it. Long posts will often have a "tl;dr" segment near the bottom. (Some people like to put it before the content.) Some people capitalize it as "TLDR" or "TL;DR".

With the advent of easy to access video you will also see the variation "tl;dw" and audio could conceivably have "tl;dl". This could be another reason the semi-colon is there: Variations are quickly recognizable. "Too long; didn't read/watch/listen" belong to the same family.

The phrase is here for now and will probably go through a few more evolutions before it settles in. My generation of internet users knows it well; the kids get to decide whether it stays or dies.

There are probably a lot of hyphenated abbreviations. Come to think of it, shouldn't most abbreviations have punctuation in them to denote the fact they're abbreviations? (I've already used the apostrophe several times, and you'd often see things like "etc.", whereas "etc" would be incorrect).

Certainly an interesting point in the case of tl;dr though, you'd think punctuation would be one of the first thing to go if you're trying to abbreviate something.