There was a bit of discussion about piracy on the Indiegames Blog. People asked me to post my own data regarding piracy's affect on sales, but I do this with some reluctance because it may come off as whining. I don't mean this entry in that way at all. I am just trying to present this stuff objectively, because data about this stuff isn't very common (many people aren't comfortable being as open about their sales and conversion rate and all that).
Okay, in this thread you can read the download numbers, number of sales, and conversion rate (percent of sales per demo download -- so 1 sale from 100 downloads would be a 1% conversion rate).
Immortal Defense was released in June of 2007, so it's been on sale for two years now. Despite that, there was no actual torrent of the full game until the end of January, 2009, because it's kind of an obscure game. It was still pirated via megaupload and rapidshare links, but those I could take down when I saw them via a single email, whereas you can't really take down torrents, and they're easier to use for most people.
Here's the conversion rate data for every month of the game's release so far (the full data for sales numbers and download numbers per month can be found in the aforementioned thread but is excluded for readability here):
aug 2007: 1.8%
sept 2007: 1.3%
oct 2007: 1.1%
nov 2007: 0.4%
dec 2007: 0.5%
jan 2008: 0.975%
feb 2008: 0.64%
mar 2008: 0.4%
apr 2008: 0.35%
may 2008: 0.375%
june 2008: 0.57%
july 2008: 0.6%
aug 2008: 0.8%
sept 2008: 0.3%
oct 2008: 1.5% *
nov 2008: 3.75%
dec 2008: 1.9%
jan 2009: 2.25%
feb 2009: 0.667% **
mar 2009: 0.85%
apr 2009: 0.56%
* October 2008 was the release of v1.1, which improved the game quite a bit, and the new demo now included a nag screen at the end which asked them to buy the game and provided a link to my site, and was also when I lowered the price from $23 to $15.
** February 2009 was when the first working torrent of the full game came out.
Okay, the above is the data, the rest can only be interpretations. The conversion rate is jumpy, and not predictable. For me it varied between 0.3% at its lowest and 3.75% at its highest, a more than tenfold difference. Because it fluctuates randomly so much, conclusions about what affects it are necessarily suspect. But it can still be put in roughly four groups (as I did above) which are somewhat similar in their average values. So two interpretations I have are:
1) The v1.1 drastically improved the conversion rate: lowering the price and providing a link to the site from the game itself seemed to greatly improve the percent of people who bought the game.
2) The release of a torrent of the game seemed to decrease the average conversion rate back to pre-v1.1 levels.
3) I don't know what caused the original drop (the first three months had a relatively high conversion rate, followed by a long time of relatively low conversion rate); it could just be related to those months being the first release of a game and the reviews of the game, which mostly appeared around that time.
Those are just interpretations though, I'm not positive the new release and price change in v1.1 was actually responsible for the improved conversion rate, it could just be chance; similarly it could just be chance that the conversion rate happened to go down so much when the torrent of the game was released. It's just speculation, but since data about this is lacking I thought I'd put this data out there.