I would be interested in learning how that experiment goes. Social hacking fascinates me and at one time I spent quite a lot of time performing "private" experiments/tests with regards to influencing forums/email lists. I would be especially interested in seeing a write up done beforehand as to your logic/reasons for doing it and what you hope to achieve and then a write up afterwards to see what the actual results were. The information is a lot less valuable/interesting to me if there is no beforehand piece of it, put in writing before actual implementation. However, it probably should not be published until you get results, just written down. Publishing it could contaminate the data as it could influence the outcome and make it impossible to tell if the money or the article was driving change.
That is a great idea. And I understand the need to keep the prediction secret till later. I just wrote this up and sent it to you as an email. We will see how things work out over the long term.
+1 to documenting the hypothesis+ prediction and the results.. I would love to see that too.. yep.. am ok with not publishing the hypothesis first too..
Best of luck.