Short Code to grab any URL parameter from the Query String
The URL Params WordPress Plugin allows you to access URL parameters in the Query String of the URL.
The plugin even allows you to specify a default value in the shortcode if the parameter isn't set, so if you want to say "Hello, FirstName" and FirstName isn't set, it could say something like "Hello, Friend!"
To specify a backup url parameter, enter multiple parameters seperated by commas. The plugin will check for each paramter, in order, until a matching one is found and return that. Failing finding any of the parameters you listed, the default will be returned. For example, you can specify
[urlparam param="FirstName, First, name" default="Friend" /] to check for FirstName, and if not found, then First, if not found, then name, and if not, then just return "Friend".
If the parameter is a date, you can also specify the
dateformat option using a PHP friendly date format, for example
[urlparam param="somedate" dateformat="F Js" /].
This is great if you have personalized links, like from Infusionsoft, as it lets you personalize a landing page with a persons name.
You can also use this to pre-fill out form fields for folks based on the querystring. For example, if their first name is passed in the URL, your landing page can greet the viewer by name and pre-fill their name on a form.