Google hosted software developers in 10 cities around the world last week. Google used the events to promote the use of its online tools and services to build web-based applications. Google also unveiled new software, including a browser plug-in called Google Gears, for viewing web applications offline, and the Google Mashup Editor, an "experimental tool" for creating user interfaces with AJAX.

In a series of presentations, Google engineers showed how developers can use APIs (application programming interfaces) for Google Maps, Google Checkout, and other services to add functionality to websites or build new applications.

The Google Developer Day events began in Sydney, Australia and ended in San Jose, California.

Gregory Renard, CTO of IT consulting company Wygwam, traveled from Brussels for the event near Bastille in Paris. He came to research whether he should start using Google's APIs for his work, which involves building proof-of-concept applications for businesses and government agencies.

Renard is a Microsoft Most Valued Professional, one of a group of hand-picked developers chosen for their deep knowledge of Microsoft products. Today he is undecided as to whether he prefers the Google tools to Microsoft's competing Windows Live APIs for web-based applications.

Google's roots are on the web but Microsoft has much more experience building tools for developers, he said.

"Google is a search company that wants to be a software company, and Microsoft is a software company that wants to be a search company," Renard said.

In any case, he's glad that Google has emerged as a Microsoft competitor because it should ensure more innovation and lower prices, he said. One question he hoped to get answered last Thursday was whether Google's APIs will remain free to use, which is important if he plans to use them for his clients.

Yvon Cognard was there to learn more about the Google Maps API, which his company uses at its site Trivop.com, which bills itself as "the first video guide for hotels". He has already been using it for some time and called it "a very good tool", although Google could do better with its documentation, he said.

Cyril Pierre de Geyer was trying to decide if his company, Anaska, which provides training in MySQL and PHP, should also offer training in Google APIs. Anaska uses Google Maps on its own website to show locations of its training centres, he said.

Google has a good reputation with developers and contributes code to the open-source community, such as extensions for the MySQL database, de Geyer said. But he has also noticed a tendency by Google to monetize its services more aggressively than a few years ago, he said, by putting more ads on its search results pages, for example.

For Google, the events should help to build a bigger developer community, which in turn should help promote paid services such as the professional edition of its online productivity applications. It should also mean more websites using Google services, which helps drive its advertising business.

Company engineers sought to emphasize the collaborative role that developers can play with Google's APIs. "We need your creativity and your imagination to drive the development of these products," said Patrick Chanezon, evangelist for Google Checkout, at the start of the Paris meeting.

Other events were held in Tokyo, Beijing, Moscow, Sao Paulo, Madrid, London, and Hamburg.