I suspect that the board is not well-characterized by a single half-life. If one attempted to fit a single half-life to the entire dataset, the best fit would be something in the vicinity of 1 post, but that’s clearly belied by the existence of people with tens of thousands of posts, much less the large abundance we have of such. More plausibly, I would describe the board in terms of several different “isotopes” of posters, with varying half-lives. The long-term-stable posters are the smallest group in terms of number of registrations, but nevertheless have a very large impact on the board by virtue of the large number of posts each of them has. And it’s precisely this sort of poster that the OP is asking about.
If you have 10 people that post upwards of 20 times a day and 1000 people that make 1 post and then disappear, which are the posters that are going to stick in people’s memories and be missed?
I think mostly people find us by accident … they have a question, they searched, and the search led them here.
They get their question answered, they don’t pay attention to anything else happening around them, they leave.
Others … a very few have read the books. (Increasingly less and less over time, as the books are hard to find and who reads paper books nowadays?) Some read the columns in their hometown alternative newspaper and found us that way.
There’s some that get here through their friends, their family members, their co-workers.
But mostly it’s just sheer happenstance … and Google.
I agree. Some of our primordial posters are like Pb-204, having been around since the origin of the Board, while others are highly radioactive and last but a short time before disintegrating.
Some popular and prolific posters have died. 
Great post out of context.
i liked his signature: ‘Yer pal, Satan’.
Lissener?
Walked off in a huff.
Satan, in case anyone was wondering, was another one who got banned.
I did too. I also remember reading that he was banned, I liked him back in the day.
Whatever happened to minty green? He (I think ‘he’ ) was one of my favourite posters and then . . . poof . . . gone.
And, gobear? Again, a fave who just vanished.
I did it. It was summer, and I needed to make mojitos. He muddled through it very well, though!
Count yourself lucky.
I agree about gobear and chowder. Just <poof!>.
List of posters who have been banned in the last 12 months:
Sevastopol
code grey
Abloyprotec
Adhay
Diogenes the Cynic
Zhen’ka
Soul Frost
Commissar
Markxxx
Le Jaquelope
Athelas
Khaki Campbell
pinguin
Mookie Blaylock
Ashen Lady
Leon497
There might be more, but that’s all I was able to find with a simple search.
I only recognize 3 names on that list. Maybe most were one-trick banners.
Phew, I’m not on the list.
Ahhh,** Mookie Blaylock**. How does such an unpleasant poster choose such a cool name?
mmm
Kyla was a grad school grad looking for a job and living back home, last I heard. She must gave found a job that’s eaten all her free time because I haven’t seen her post in awhile.