The acquisition was noted on both Writely's main Web site and on a blog run by co-founder Claudia Carpenter.
"Yes, we've been acquired by Google," Carpenter wrote. In a frequently asked questions page on Writely's site, the word processor company says it doesn't yet know what the implications of the sale are.
"We haven't yet figured out all the details," Writely said on its site. "Coming to Google will eventually give us a leg up on getting things done that we just haven't been able to with our tiny team."
A Google representative confirmed the deal in an e-mail. "We acquired Writely for the innovative technology and talented team," Google said in a statement. "We're thrilled to have them here." The purchase price was not disclosed.
Google declined further comment, though it did post some information on its own company blog.
Google noted that Writely remains in beta and that there is currently a waiting list for people wanting to use the service.
Writely was launched in August of last year by privately held Upstartle. The companyin December, one of several features it said would eventually be part of a paid premium service, once the program emerged out of beta testing. Writely can also handle documents saved in the format, as well as files created by OpenOffice, an open-source rival to Microsoft Office.
There has been considerable speculation that Google would look to create a Web-based rival to Microsoft's dominant software suite, speculation that was fueled in October when Google announced awith Sun Microsystems, which has been a leading backer of OpenOffice. That same month, Google also said it was to help work on improving OpenOffice.
Writely is one of several companies that offer.
In a previous interview, Carpenter said the company has considered creating a hosted spreadsheet to complement its online word processor. But the company's strategy is to emphasize collaborative features rather than simply re-create Microsoft Office online.
"The last thing we want to do is compete with Microsoft head-to-head," Carpenter said in February.
Microsoft noted that more than 400 million people use its Office product.
"Microsoft Office is the clear leader in what has always been a very competitive space," Microsoft senior marketing manager Erik Ryan said in a statement. "We welcome competition in the marketplace and believe it is healthy for the industry as a whole and good for customers."
CNET News.com's Martin LaMonica contributed to this report.