Well, as I see it... suppose you can collect the data regardless of whether you consider it open or proprietary. Under the "open" model, you get the advantage of (at least from some perspectives) doing the right thing by the community. The downside for you is that emerging competitors can take your data as a starting point rather than needing to go through the effort of building their own data. If you choose to keep the data proprietary, it could be one of your competitive advantages.