Google closed the site to new subscribers shortly after announcing the purchase in order to work on migrating the service to Google's software stack. The site went into full operation late last week.
Writely, a promising Web 2.0 startup, was launched last summer by the three-person development firm Upstartle. Financial details were not disclosed.
Writely, which remains free, enables subscribers to store and work with text documents on the Web. Documents can be shared and edited collaboratively with other Writely subscribers.
Google has become an aggressive buyer of software startups. Its recent acquisitions included @Last Software, a maker of 3D modeling software; Measure Map, a blog traffic tracker; dMarc, makers of a radio advertising platform; Android, a mobile phone software maker; and Dodgeball, a maker of mobile social networking technology.