Folder versus asset - Whats the difference?

Folders are more of an organizational tool than anything else. They provide a place to store related programs, smart campaigns, or local assets inside of a program. They have no purpose in the actual flow of a campaign.

Local assests are exactly what they sound like - any "thing" that is specific to the program it lives under. Local assets can be emails, forms, landing pages, etc. 

The item you are seeing with the little mailbox icon is an email program, which is the overarching controller for sending/testing an email. You will still need to create a local email (or use a global email) in order for the program to run. When you are seeing the control panel view, that means that you have selected the email program, not the email. 

Does that make sense?

Thnaks!  I am still a little unclear as to the benefits of either one.  We are currently using the folders in a setup now to list the campaign title, then have sub folders for assets, then have folders for e-mails, lists, etc.  I am thinking the folder for the e-mails should not be a folder and should be an asset (mailbox) and then have the e-mails listed under that.  I was only using this for the first time and setting following the setup we used in training so there may be a better way or preferences one way or the other but thats what I am unclear on.

I do appreciate your feedback and if you understand this than please let me know.

Okay, I think I better understand what you're confused on. The "asset" you are describing with the mailbox icon actually isn't an asset at all, it's a program. There are four kinds of programs: Engagement, Event, Email, and Default, which all serve their own purposes. I'll use an analogy to try to clear things up.

Think of programs as large file cabinets. You can have the four different kinds (listed above), and they each represent a completely different part of your "business" ( aka your marketing strategy). They encompass everything that has to do with a specific marketing effort. The drawers are one way to use folders, i.e solely for organization purposes. Inside the drawers (folders), there are the hanging folders (a sub-set of Marketo's folders), also solely for organization purposes. Inside of those are your local assets (emails, LPs, forms, etc.).

Overall, you want to use folders to the extent where everything is organized. Assets are completely unrelated to folders, other than the fact that you can store assets inside of them. Programs should contain all of the above, as they need it all to operate correctly.

Yay or nay?

I like to view my assets such as emails, lists, and landing pages in a folder, within a program, inside a campaign folder.  It's just easier for me to see because I look at all of my files on the navigation tree.  

One of the projects I recently completed with a consultant, organized things slightly different.  There's 11 email programs and 1 email program which is called the central assets which has the original versions of the emails that I created.  He had an action flows folder for the campaigns.  Within the 11 email programs he has an updated version of the email of my original email a list that go with the campaign, and the outbound campaign. He created a program of assets to contain central items rather than having them inside the individual email programs or have them in Design studio.  

Either way works for me.