I use this for short term things, like getting a download link, or signing up for something I only need once. The maximum time you can use the address for free is 3 weeks or 10 email forwards, whichever comes first. If you want to extend the amount, and time, you will need to upgrade for their paid service.
But I wouldnt pay. For long term websites, and things I will be accessing regularly, I use GishPuppy.
I saw some of the earlier reviews and wanted to address one thing:
For all those people that have *problems* you need to change your settings. 1)You have to disable the challenge response system. That way, an automated messaging service doesn't need to click on anything, they just send you whatever you need (like a download link). It doesnt *require* manual intervention, that just an option you can turn on/off.