I've been searching around GetResponse as well as searching the Internet on how to do this, but I can't find anything so I thought I'd ask the e-mail ninjas here.
I'm using GetResponse and I'm using their auto form to build my list: name, e-mail, blah, blah. It's my own landing page on my own server. I'm using different traffic sources to send people to this page, so I'd like to be able to track in GetResponse where these people came from. That way, I can look in GetResponse and say "Oh, people who signed up through Google have a 30% open rate but those who signed up through Bing have a 40% open rate, or whatever.
Ideally, if I could just pass variables onto GetResponse from the link to my landing page, that would be great. So I could send people to
http://www.example.com/landingpage.html?variable1=google
I'm not familiar with GetResponse's API or interface, but the simplest way to do this assuming that GetResponse let you have custom fields in their signup would simply be to pre-populate a hidden field in the form with the value that you've passed from your traffic source.
In this case, it'd be as simple as something like
<input type="hidden" name="source" value="<?=$_GET["variable1"]?>">