I've never been convinced that file sharing really has a negative influence on physical sales. As the RIAA and others advanced their war against file sharers, I thought it was pretty appalling that they never produced any compelling evidence that file sharing was the cause of reduced CD sales (for example).

Now, another nail in the coffin of that circumstantial argument. Slashdot is reporting about a Dutch studying finding the file sharing has positive economic consequences:

"In a study conducted by TNO for the Dutch government the economic effects of filesharing are found to be positive. According to the 146 page report (available for download, but in Dutch) filesharing is good for the prosperity of the Dutch: with filesharing more media are available, even though this costs the media industry some profit. One of the most noticeable conclusions is that downloading and buying are not mutually exclusive: downloaders on average buy just as much music as non-downloaders, but they buy more DVDs and games then people who don't download. They also tend to visit more concerts and buy more merchandise."

Unfortunately, it looks like the original news article and the report are only in Dutch. But, anecdotally, this makes a huge amount of sense to me for two reasons. First, these findings about media use are similar to findings about online sociality. For a long time, people thought that online social life was a replacement for offline social life, but evidence continues to mount that people who are more social offline are also more social online. Similarly, I think the most reasonable starting assumption is that people who use media more will use it more in both contexts.

Secondly, I think the hardest thing to measure about file-sharing is the degree to which sampling media via file sharing leads to more purchases. I, for one, can't count the times I've downloaded a song, an album, a movie, a TV episode from BitTorrent, and then later on purchased that same media or some other media in a legitimate form (CD, DVD, iTunes). Often it's because I'm not happy with the quality of the download, or I want the liner notes on the CD, or similar.