When you invite a friend, CloudMe gives you extra 500MB. You can get up to 16GB. If DropBox, invited person has to install its application into a PC to get the extra space. DropBox prohibits to install the application into a same PC multiple times. It means you can not invite your family who use your PC to get the extra space. On the other hand, when invited person makes an account, CloudMe sends an email with a confirmation URL. Soon after he click the URL, you and he can get the extra space. It is much easier to get the bonus than DropBox. Please try this URL to get +500MB (and give me +500MB :-D ). https://www.cloudme.com/en/signup?c=15bbbc6b1607c232acd30036e2b51d66