SpiderOak is a solution for syncing and sharing files. When you first start the application, it will prompt you to create a new account. Just for creating an account you get two gigabytes of storage on the cloud (the Internet). After that, you can tell SpiderOak what files you want to upload to the servers from your computer. There are two ways to do this. By default, the application shows you the basic view, which allows you to check a file category. Those categories are Desktop, Documents, Movies, Music, Pictures. What the application really does is back up those folders from your computer. The advanced mode, on the other hand, shows you a tree structure of your hard drive and you can select any folder or file that you want uploaded.
Once your files are uploaded, you can access them from any computer with SpiderOak. They can also be shared with both SpiderOak users and those who don't have the program. SpiderOak allows you to share a "share ID" or to simply send an e-mail to people with a link to the files or folders.
Apart from uploading and sharing, SpiderOak can make sure that several computers have the same files. To do that, simply download SpiderOak on a couple of computers and tell it which folders to sync. The application will automatically download files from the cloud once they are uploaded from another computer. There is also a premium account which has a lot more features and options.
The only thing that this program lacks is a quick share folders to just copy files into. But if you don't need that, SpiderOak does a good job of sharing files and syncing a couple of PCs.