I thought I'd throw this out to see what others think:
The majority of ff programs state that it may take 6-8 weeks for mles to post to your account. But at the same time it's been my experience that miles from several companies post within 2-3 days on a regular basis (Bankdirect and the Cinemark offer on American as examples). So in this computer age of instant messaging, etc. why does it still take that long? A week or two, even thrity days in an extreme case, but two months? C'mon!
This is on my mind because I'm anxiously waiting for a good chunk of miles after selling my home in Sept. and here I am down to the 8 week wire and so far no miles. It's a pain to have to be calling and checking up half a dozen times until the miles post (a la Netflix ).
I've often wondered it it's not part of their 'diabolical plan' thinking that a certain percentage of people will have been distracted or have forgotten about the miles if they don't post 2 months down the road (the unforgiveable sin for ft'ers, of course )

The home-sales one is easy to understand: you've essentially purchased AA miles through some sort of middle man. (A mortgage broker or whatever.) The broker is going to invest your payment for the miles as long as he can, and then manually purchase the miles from AA. It's not a system problem - it's a human process.

I'd think that the "buffer" is there so they can check for fraud or/if something suspicious happens (Hilton for $2) or can wait until any return period for the qualifying purchases have passed...

Some points/partners post almost instantaneously. They're "live" with the airline or hotel and points post just as soon as the merchant gets around to it.

Others send over points in batches, on a tape, perhaps only once a month. Depending on when you earned points in their cycle, you might miss one transfer and the next one could be a month away, and then a bit of time until the airline runs the tape.

Shopping merchants tend to take longer to post, precisely because of the potential for item returns as noted above.

But in most cases there's absolutely no reason for miles to take as long to post as they do... Amex is good about posting points for monthly charges, but notoriously slow about posting bonus points for instance (try 12-14 weeks!).

Delta now posts miles on the same day of the flight. AA, UA, USAir, Hilton usually credit miles a few days later. Bank Direct sends in accounts info to AA a few days after the end of the month and thus posting on AA could be 4 or 5 days later.

Hyatts, Priority- post points within 3 to 5 days. Marriott can take a week with followup emails required about half the time. Choice is extremely slow - many times 2 or 3 weeks later and several times I had to fax in the receipts to get points credited.

Qantas is terrible. They ignored my emails.

If the customer is going to get 20,000 miles as a by-product of his purchase of the goods or services, what is merchant/broker/whoever paying the airline for those miles? Anyone have any knowledge of that part of the deal that we as customers don't see?

Generally, the merchant will pay the airline somewhere between $0.01 and $0.025 per mile. Big purchasers (Citi, Amex, etc) toward the low end and small businesses toward the high end. The exact price paid by merchants like Citi are closely guarded secrets while the high end is usually disclosed publicly by the airlines (often on their websites). AA, for example, will sell 250k miles for a total of $6,162.50:

https://www.orderaamiles.com/orderAAmiles/pricing.jsp

I wonder if any deals every happen at that price - I guess this is just to make us believe our miles are worth a lot...

My guess is that there are three reasons that companies say 6 - 8 weeks.

1) Batching (as has been mentioned). In order to get the best price, match up needs, deal with behind-the-times technical issues, doing large volume makes sense.

2) Percieved customer service. If we're told 6 - 8 weeks and it really takes a week or two, we feel pretty good, don't we?

3) Cash flow. The merchant can wait a month or so to buy the miles. That's a month or two of cash that stays in his "pocket".

Gleff's example of Amex is on the mark. "Normal" transactions seem to post in most programs quickly. It's the "specials" (Sprint, hotel bonuses) that always seem to take "forever".

There is another reason some companies quote 6-8 weeks for miles to post: that is about the time it takes for the average (non-FT) flier to have forgotten all about it.

Thats nothing. I bought my house in June, went through Lending Tree.com to find my real estate agent. Sent the HUD-1 on July 14th. 8 weeks go by, no miles. I emailed and called Lending Tree about it, they confirmed that my HUD-1 was received and that I am to get 32, 915 miles. They researched it and said that my miles will post by the end of November. Well, here it is the 14th of November, not much time left. Who thinks that I will have to call them again in 15 days when no miles post?

As I mentioned in the OP, my 8 week time frame was rapidly drawing to a close (tomorrow, the 15th, in fact). But this morning, without even a single call on my part, my 86K miles appeared in my UA account, restoring my faith in the system as a whole. The end must be near!!

What's suspicious about Hilton?
I don't get the suspicious in suspicious......

Priority gives the hotels 72 hours after the checkout to verify that the points issued are correct. After that 72 hour period, the points are posted on the next day. This is done to make sure points aren't issued to nonqualifying rates, and for any bonus points that need to be issued.

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