Google's nascent 3-D experiment is enabling a bit of a problem for some: Google Earth pollution.

First off, there is the litany of Web developers using Google Earth to bring attention to pollution.

PlanetHazard, for instance, lets you search for things like the top 10 polluters in Arizona or the proximity of a top polluting company to schools. There's also ways of tracking light pollution.

Commendable efforts abound, such as The Sierra Club's use of Google Maps to detail the supposed impact of drilling for oil in Alaskan. like this one, in which the Carnegie Institute apparently used Google Earth to study deforestation.

But to some, there's another kind of Google Earth pollution, one on the maps themselves.

Since late April, Google's been making available a number of free programs to create 3-D images, then upload them onto Google Earth maps, or the 3D Warehouse, a place where the graphic can be downloaded by others.

The goal was to bring 3-D to the masses. It's sure working.

Take a gander at the Empire State Building, via Google Earth's "fly to" feature. There's now several 3-D images of buildings near the Empire State Building, including one of the Chrysler Building.

To some people, these new images only add to the existing clutter on the maps. The Google Maps screen was so filled with names of locations and businesses as the image resolves into Manhattan that, at one point, all the scrunched-up names and symbols totally obscured the satellite photo.

As to the clutter and in Google's defense, Manhattan is a special case, where there are hundreds of listings to cram onto the map. And Google makes available a quick and relatively painless way to get rid of all of the, assuming here, paid listings.

Of course, the 3-D features showing up on Google Earth can all be avoided by not downloading the network software Google makes available.

And, a lot of Google Earth users like the new additions, and all the other map references. The 3-D imagery, especially, is a kind of high-tech graffiti that adds an interesting flavor to the maps. The King Kong image for the Empire State was a nice touch, for instance.

So in a way, for a lot of people it's kind of welcome clutter.

But for some, the erasers that Google Earth provders aren't as apparent as they are to others. And it's surely a challenge for anyone, even the biggest Google Earth devotees, to make use of all the information being presented at any one time.

So it seems that Google's got to walk a fine line between cute/useful and so cluttered it's tough to make things out.

(Note: This story was augmented May 21 to incorporate some of the sentiments expressed in the feedback section below.)