Update: here is a blog-post which best explains the distinctions between the various org types involved in the AppExchange publishing process:
Understanding the AppExchange publishing process, environments, and app lifecycle
As a brief summary, though, here is an explanation of the roles of each type of org:
Managed Package Development Org - you will need to have ONE of these for each managed package / AppExchange app that you have. Licenses for customers using each packages developed in each of these orgs can be more easily managed through the use of the LMO org. AppExchange Listings for each of these apps can be more easily managed from AppExchange by specifying your CRM/LMO org as your AppExchange Publishing Org / APO (see below). Development orgs come in 2 types/sizes:
a. Regular Developer Edition (DE) org - has 2 System Admin users, and limited data storage. Available from developer.force.com
b. Partner Developer Edition (PDE) org - a special "super-sized" development edition type appropriate for AppExchange application development. Comes with more users and higher limits.
LMA - the License Management Application. Each Partner should have ONE org, typically their CRM for Partners / Business org, that has this special application, available only by request from Salesforce.com after you have become an official Partner, installed in it. Whatever org has this app installed is dubbed the "License Management Org" / LMO.
LMO - License Management Organization / CRM for Partners / Business org - once you have an established ISV/OEM contract with Salesforce.com, you are given an Enterprise Edition org with 2 free licenses and one or more special applications pre-installed into it. This org, and these applications (the License Management App, and sometimes the Channel Orders App) are tools for ISV's/OEM's to use for:
- tracking which Packages and Package Versions you have uploaded for each of your various AppExchange packages
- managing customer Licenses to your AppExchange packages
- supporting your customers through Subscriber Grant Login Access / aka the "Partner Black Tab" functionality
- submitting ISV Channel Orders to Salesforce.com to collect revenue from your sales
APO - AppExchange Publishing Organization - AppExchange terminology for the org that you would like to be the AppExchange listing management hub for all of your company's AppExchange apps/listings. As a best practice, make this your LMO/CRM/Business org. This will allow you to manage all of your AppExchange listings from one place. Once you have established this org as your APO, you'll be able to login to Appexchange using your APO credentials, and see and manage ALL of your AppExchange packages/listings which you have linked by clicking Manage Organizations > Link New Organization from the Publishing Console.
- TMO - Trialforce Management Organization - where you manage your company's custom branding and create/manage your Trialforce Master Orgs. Typically this is a separate org from all of your other orgs, and is some type of Developer Edition org.