You'll be able to drag and drop a file into Transfer and then send the other person a link or a generated email. Sharing has granular controls for file access (you can set a password or an expiration date) and you'll get notified if the file has been downloaded. The person on the other side doesn't need to be a Dropbox user and will get a copy of your original file.
Users will be able to stylize their Transfer download page with a different background and businesses will be able to brand it with their logo.
There are many other file sharing services out there but they're limited to much lower file sizes - 8GB, 10GB, 25GB.
Dropbox Transfer will begin beta testing with select Dropbox customers and will launch to all Dropbox users soon.