Whether you call them mash-ups or hacks, third-party edits to the mapping systems offered by Google and Yahoo! are springing up all over the place these days. From tools that help you find the nearest delivery joint to programs that let you plot maps of your friends, these online tools are helping Internet users gain access to information that was out of reach just a few years ago.

That fact hasn't escaped the major media either. AP reporter Jonathan Drew has coverage of the mapping tools in two articles this week.

From Eye in the sky, on your computer:

Google, Microsoft and Yahoo have all allowed programmers broad access to their mapping technology -- and it's becoming clear that whoever captures the hearts of developers now stands to capture valuable Web real estate that could mean profits later. Google, for example, reserves the right to someday place ads on maps generated with its software.

Within weeks of Google launching its mapping feature in April, Web developers had figured out how to code their own Web pages to include a map in their sites. Among those sites was http://www.housingmaps.com , which plots Craigslist real estate listings on a Google map and http://www.chicagocrime.org , which lets users plot police crime data over maps of that city.

"It's in a way a bait and switch because it's making this cool free functionality available to anyone who wants it so its sort of hooking people in," Holovaty said. "It's inevitable that Google will start putting advertising on these maps. So they have hundreds of maps on hundreds of decentralized web sites and all of the sudden they're going to have advertising. And I think we'll start to see a backlash when that happens."

From Five Things You Can Do With Mash-Ups:

Among the first mash-ups created using Google Maps, www.chicagocrime.org, lets users browse crimes in a number of ways, including by crime type, date and location. Apartment hunters have referenced this site in deciding where to live, while community activists have used it to illustrate the plight of their neighborhoods.

A more recently created site, www.seattle911.com plots 911 calls on a map of Seattle within a few minutes of them being placed, using data from a government Web site.

If you've ever had trouble finding that obscure bit of information on the Web, www.doubletrust.net might be the site for you. It combines search results from Google and Yahoo, displaying them on the same page. If you favor both search engines equally, DoubleTrust will present a list of results that both sites rank highly, followed by lists of "orphans" favored by one engine or the other. You can also tweak the site to display rankings differently, depending on which of the search engines you prefer.