PC World has an article about Google "eating its own dog food," i.e., using Google Apps internally. This part is not surprising, but worth repeating:
All of the applications "were really built from the ground up to focus on collaboration," Glotzbach said in a follow-up interview. "Using them ourselves has really helped us expand on how we work with one another, making [communications] more real time, making it easier to collaborate when we're traveling, when we're on the road, from a mobile device, from any PC or workstation inside the company."
He describes an incident in which he began a document outline, shared it, and collaborators built the document together, like a wiki.
But Googlers also use Microsoft Office and OpenOffice for their work. This point is a bit downplayed in the article.
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