Is There an Easier Way?
Since farmers work only the areas proven most profitable, you now have a nice list of hunting grounds for your own pursuit of gold. But actually, there's another way to profit by your knowledge of professional farming patterns that doesn't require you to fill your friends list with the names of people you who aren't actually interested in chatting with and to scope out what these relative strangers are doing. All you really need is some information about shift changes.
Shift Changes
6/12 Server Time
The U.S. WoW servers are set to Pacific Time. Though Jakarta's time zone is 14 hours ahead of this, all the Indonesian farmers (as far as I know) change shifts at 6 AM and PM Server Time. This is also true of most Chinese farmers.
Some Chinese Farmers Are a Bit Early
A minority of Chinese farmers change shifts 1.5 hours earlier than that; i.e., 4:30 Server Time, both AM and PM.
Halftime Quotas
If there are half time quotas imposed on farmers, they will be due at noon and midnight Server Time for most farmers, and at 10:30 AM and PM for a minority of the Chinese.
Sell Off Times
Farmers usually start spamming the AH with their sales about half an hour before their quotas are due.
Grace
If a farmer has had trouble moving product and is behind quota, he can sometimes prevail on his partner to let him stay on the account for a few extra minutes so that he can continue to push his goods. I've seen this "grace" period stretch to half an hour, but only for farmers whom I know to be on particularly good terms with their partners.
Summary
So to summarize, there are major daily sell offs on the IF Trade Channel at around 5:30-6:30 AM and PM, and Minor sell offs from 11:30-12:30 AM and PM, and at 10-11, and 4-5. Most of the items are sold during the 1 st half hour of the period, but the closer to the "close of business" it gets, the more desperate the sellers become.
Where You Come In
What Farmers Want and What Farmers Need
Though a farmer would like to get as much gold as possible for her items so she can increase her cache, she has to collect at least enough to satisfy her quota.
Catch the Blowout
You will see a pattern starting at around 5:30 AM and PM every day. Characters will start hawking items on the IF market channel at around 11:30. The prices will probably be competitive but not lowball.
It Doesn't Hurt to Let the Farmer Know that You're Interested in Her Item Early on
If a price isn't stated in the spam, you can send a whisper and ask for it. As time passes and the bewitching hour nears, the prices of any unsold items will drop drastically. The fire sale has started and true bargains are to be had. Whisper enquiries to the same farmers you've queried 20 minutes before and you'll find that they're now asking a lot less. Make an even lower counter offer and don't be surprised if it's accepted.
If you make a lowball offer on one of these sell-off items at about 10 minutes before the hour and it's rejected, don't be surprised if at a minute or two before 6:00, the seller gets back to you and, to the best of their non-English-speaking ability, asks you if you're still interested in their item. (That's why it can be a good idea to send the farmer a message or two earlier in the session. You want your name to spring readily to mind when their desperation hits the critical mark.) They may still try to get a higher price out of you but if you stick to your guns for a minute or so of bargaining, you'll probably get the item at the price you named.
Of course, farmers who stay on past the ends of their shifts, while their boss and/or partner breathe impatiently down there necks, are even more amenable to agreeing to ridiculously under-market offers; so keep looking for bargains after 6:00 as well.
A Single Example (Though I Could Provide Many)
I'm not saying that at sellout time, farmers will settle for pennies on the dollar (sorry, I mean copper on the gold), but they will sell an item at a price that will let you make a nifty profit from a quick resale. For example, I've purchased Krol Blades from farmers who were very well aware of their true market value for 600 gold and then resold them in the AH with my auction being bought out at 950 in less than 12 hours. I'd say that earning 350 gold overnight compares well with most of the techniques you'll find in forums on gold farming.
(By the way, a humorous sidelight of my first such Krol transaction is that the Blade was the first item I ever listed in the AH at anywhere near the thousand-gold range. As soon as that item was in the AH, I started getting whispers from strangers—in Chinese! I know this seems to belie my earlier contention that not all commercial farming takes place in China, but I still stand by that assertion. Apparently though, Chinese farmers themselves are under this same misapprehension since they seem to take it for granted that anyone auctioning such a high ticket item had to be one of their own.)