TextFlow was built using Adobe's AIR software, which lets Web applications run even when a computer isn't connected to the Internet, and which also provides easier access to files on a user's machine. Because of this, a user can import Word documents to TextFlow by dragging and dropping them from the desktop into the browser. She can also make edits offline, although it is not yet possible to merge documents using TextFlow while offline.

TextFlow launched two weeks ago, and (as with many other Web apps) new features are still being added. The most important feature on the horizon, Shalit says, is the ability to share a document without needing permission from the original owner. Most online word processors consider a document to belong to a particular owner who can then give other users permission to read, comment on, or edit it. With TextFlow, the document's creator can still select how to incorporate others' changes into her version of the file, but she doesn't control how the file moves among other users.

Nicholas Romano, an associate professor of management science and information systems at Oklahoma State University, who studies online collaboration, says that merging text is a complex task, and it's not always obvious to users how making changes to one section of a document might affect another. "A lot of these tools are being used by people without experience working collaboratively," Romano says. He believes that it would be useful for Web word processors to include better collaborative features, and he adds that a timeline or agenda showing tracked changes could make collaborative writing even easier.

Unlike desktop word-processing programs such as Word, TextFlow is not designed for layout. The interface includes only the basic tools needed to edit documents, and it doesn't currently support links, tables, or images. The software is free for users to try, but Nordic River charges $99 per individual for a year of professional use. Shalit says that the professional version will get additional features in the future. The company doesn't primarily expect to support itself with sales of the product, however. Instead, it hopes to make deals with others, combining TextFlow's capabilities with those companies' products.