A Tumblr blog is fairly simple to use, which means you may be able to add a few functions to it to help it serve as a simple campaign page.
If you already have a tumblr account (with an appropriate email address) that you will use for this campaign, skip this step.
You need an email address to create a tumblr. Get an email address appropriate for your campaign. Visit http://www.tumblr.com and fill in the email address, a password, a username, and click Sign Up.
A good Domain Name
You probably do not want to call your campaign tumblr "mycampaign.tumblr.com" -- the .tumblr. in the middle is extra typing to no purpose. If you already own an appropriate domain name then skip to the next step to associate it with this tumblr -- but if not, buy one from an appropriate hosting service ( e.g. http://badger.com )
Below, we will call this hosting service your 'registrar' since it is where you have registered your domain name.