ericjuden

This plugin allows you to use $_COOKIE, $_SERVER, $_SESSION, $_GET, $_POST and $_REQUEST data in a Gravity Form through the merge tags of a field. I’ve only really tested this using a hidden field.

Gravity Forms Extended Merge Tags

It's amazing how few people seem to know about this plugin. Incredibly simple, but also really helpful when using $_SESSION variables to track website visitors.
I use it to get referring website data, so I can easily store it in a $__SESSION variable. Then when the visitor fills out a Gravity Form, I can pass along the stored vars.
I crafted a Lead Source Tracking for Salesforce script that uses this plugin to pass along the details to Salesforce when a form is submitted.



Brilliantly simple

This plugin allows you to use $_COOKIE, $_SERVER, $_SESSION, $_GET, $_POST and $_REQUEST data in a Gravity Form through the merge tags of a field.

Janis Elsts

Normally when you login to your blog WordPress will create a session cookie that is used to authenticate you. If someone was to steal the cookie they would be able to use it to get full access to your blog without having to know your password. This plugin prevents that from happening – it makes the cookie specific to your IP address, so it won’t be usable from a different computer.
Use this plugin if you have a static IP. If you have a dynamic IP address and it changes often you will get logged out frequently.
A bit more info can be obtained from the <a href="http://w-shadow.com/blog/2008/07/12/safer-cookies-plugin-for-wordpress/" title="Safer Cookies homepage" rel="nofollow ugc">Safer Cookies homepage</a>

Safer Cookies

Ties the WP session cookie to your IP address so that it can't be used to get access to you blog from another computer.

Gravity Forms Extended Merge Tags vs Safer Cookies