Dropbox file sharing

I had applied for a Dropbox invite about two months ago and was very excited to finally receive it today. Then I saw that Dropbox in fact entered public beta today. So, basically everybody can now use it so the invite wasn't worth a crap.
Nevertheless, I installed it in Ubuntu on the Dell and it looks very good. It's simplicity itself. You have a folder that you open from a panel icon which gives you your dropbox. Anything you put in here is automatically uploaded to their servers.
You can get into your dropbox from anywhere just by browsing to www.getdropbox.com and filling in your username and password.
This will be very handy for bringing documents, photos and music when I go abroad and for sharing stuff with people that can't be conveniently emailed.
There's 2GB of free storage with every install and you get 10 invites (why invites when it's in public beta?). I wonder could I use these 10 invites to bring my free storage space up to 22 GB? Probably yes, as long as I have 10 more different email addresses.