No, the gp has a good point. These articles seem to come up every week on HN. The point is that it's super easy to write something that syncs a folder. You can start with rsync and a cronjob, and just go up from there. Dropbox is fantastic because they haven't solved the easy problem (sync a folder on a single platform when nothing goes wrong), they've solved a very different hard problem -- sync a folder across multiple platforms, deal with corner cases, handle errors gracefully, and wrap the whole thing up in a very easy-to-use GUI.
These things aren't dropbox replacements, they are reminders that dropbox is a unique product.