We have no way of knowing how many eBay members actually come to these forums but I'd imagine it would be a lot fewer than the 3% you suggest, and I don't believe there are as many as a million sellers in Australia either. Nevertheless, for every person who puts pen to paper to complain, I'll hazard a guess that there are another 100-odd who don't, and simply suffer in silence, or give it away in disgust.
However, using your 'statistically irrelevant' extrapolated figures of 0.33% of members who are unhappy with the way eBay runs their business, that would suggest that 99.64% of users are quite happy with the way things are going, yet my own personal observations from conversations and discussions with people in the real world who use or have used eBay would tend to indicate that the real figure is nothing like that. In fact, more than half of the people I've spoken with about eBay in the last 12 months or so have been less than satisfied with their buying or selling experiences.
