Question: Im currently researching how to handle lead generation forms. 

I came across a website which has 3 slightly different forms for downloading a white paper, downloading an ebook, and downloading the trial.The trial download form is the shortes.

Trial Download fields:

* name
* company
* phone
* email

White paper form fields are the same but have 2 more fields:

* job positon
* country

The ebook form has trials form fields + state field.

I can not wrap my head around this. 

Why would they have those differences in forms? Does this strategy have a name?

Also, i want to add on this particular site, if you fill out a form once, the info you already entered is auto filed on the next form you would fill out.

So, if you get a trial first, you would only need to fill out 2 more fields for the white paper.

But who is to say that most people would first get the trial, and later a whitepaper? Does this even make sense?

Answer: 
For anyone interested I found out what this is all about. Turns out this is called **progressive profiling** in marketing and it's a way to ask a prospect lots of questions without the need to stick them all on a single form. 

sources:

<http://www.hubspot.com/blog/bid/33993/HubSpot-Forms-Now-Feature-Progressive-Profiling-and-a-New-Interface>

<http://www.4thoughtmarketing.com/Eloqua-Progressive-Profiling-Forms/>

Edit:
Does going through all this just to have 1-2 less fields even make sense?

It seems so:

<http://www.marketingexperiments.com/blog/internet-marketing-strategy/lead-generation-testing-form-field-length-reduces-cost-per-lead-by-10-66.html>

This study suggests 1 less field = 1% more conversions.
This strategy looks like a reverse-common-sense implementation. The most guarded of my personal information is my phone number, followed by email, and then anything else from the list. 

If I had to do this, I'd tag the most valuable asset with direct contact information of the person downloading it, not the other way around.