Are small startups the target user? I own a small business that uses all of these services. But in the case of dropbox, team members see when files change. Google docs is google docs and file changes are pretty clear. We use lighthouse house for task management and are in constant communication on google talk but we are less than 10 employees.
Does this make more sense for the 30 person company? But at that level I would assume we are investing in a more centralized project and content management platform, box.net?