Just because there’s an API doesn’t mean that the data is truly on the web or, in other words, just because a garden has a gate doesn’t mean the walls are less effective. Google could put up a toll-booth or an immigration check-point at any time. For instance, in the early days of Yahoo Pipes, Google Base access disappeared suddenly. This was likely due to load issues, but nothing would prevent similar actions from being taken for competitive reasons.

As far as not preventing sites from hosting their own feeds, Google needs to do better than that. By providing a strong incentive to use a closed infrastructure, Google carries a large enough carrot to strongly affect the behaviour of effort-optimizing small businesses. If a realtor (or a real estate service firm like Canada Placemarks) has limited resources and only sees benefit (SERP position) from publishing to a closed system then they’ll publish to the closed system, whether it’s a semi-open system like Base or a less-open system like My Maps.

I think it makes business sense for Google to use My Maps and Base (and YouTube, and Picassa, and…) to host data that can be served in SERPs. Heck, until recently I was advocating that Google use this approach. It’s easier to manage, and it gives Google a competitive advantage in delivering relevant results. I’m just concerned that this strategy is warping the web.