Adding Mac support didn't make DropBox any more complicated for the end user. I suspect that's not strictly true. Mac OS X and Windows file systems are subtly

Adding Mac support didn't make DropBox any more complicated for the end user. I suspect that's not strictly true. Mac OS X and Windows file systems are subtly different in features (hard/soft links, aliases, .lnk files; files with multiple streams; various Finder annotations to files), and I suspect that once you sync to both Windows and Mac you will run into weird issues. Of course, syncing to multiple platforms is probably only something "power users" would do, and they can tolerate some teething problems.