It's now been about 18 days since I did my little WOW gold giving experiment and the results are not as I expected. To update you it worked like this
1) Send 40 random World of Warcraft players 1 gold each through the in-game mail system with the simple message "Merry Xmas."
2) The purpose was to test basic reciprocity is response to an unsolicited gift.
Results:
40 Gold sent to 40 random people.
8 Gold returned.
1 Gift given in return (2 Super Rejuvenation potions - value about 1.4g)
3 personal message as follow
1) "Ditto" (Action: gave super rejuvenation potions)
2) "Lol, do I know you?" (Action: nothing, kept gold.)
3) "You may have the wrong person" (Action: returned gold)
Analysis:
About 77% of people simply kept the gold and did not reply or send anything back. 20% of people returned the gold. Only 1 person acted out of reciprocation. An interesting thing to note is that the people who returned to gold did so mostly within the same day (7/8 within 48 hours). The gift was also given within the first day period. Only 1 reply came more than a week after the start of the experiment, and that person returned the gold with no message.
Something to consider is that many people use automated mail openers which may prevent them from seeing the message at all. They simply open the contents and discard the message thus the reciprocation trigger never fires. It is also possible that my free gift has essentially no value. 1gp for a level 70-80 character is insignificant, but I don't have 40k gold to throw at an experiment, so I will have to tune it in other ways.
Further research:
I may try and target lower level players who are more likely to not have such programs (assuming they are not alts) and also whom are more likely to appreciate small gifts. Alternatively I could send another 40 gold to the same people. I have thought about just giving the gold in trade, but I'm worried about that being "spammy" so I hesitate to do it.