Quiestion on understanding the @ in powershell and needing confirmation

Question

I came across the following script:
Get-ADUser -Filter * -SearchScope Subtree -SearchBase "ou=East,ou=SalesRegion,dc=Nutex,dc=com" | Set-AdUser -Replace @{title="Account Executive"}
I did not really understand the why the @ is used I did some searches on it
http://stackoverflow.com/questions/363884/what-does-the-symbol-do-in-powershell
they spoke about this being used to denote arrays.   However, they said if a value is comma separated its seen as an array anyway.  They did go on to say this is required for
Associative arrays.   I looked up associative arrays and got the following:
Associative arrays. Thus, you can access each property by entering the name of the property as a string into this array. Such an arrayassociates
each key with a value (in this case the key Home is associated with the value normal).
This tells me I think that the script I was looking at after the pipe had an associative array as we entered the name of the property "title"  and then it was associated
with the value "=Account Executive".
So when I see something like that I am seeing what is called a associative array, and these are vehicles that can be used to change or work with properties?  Its an array because
it can be dealing with multiple (or single depending on how many) objects.  In this case the object was the title property in AD.
Thats kind of how I am seeing this but its complex ideas and I am trying to break it down to simple thinking in my head.
Anyway before I commit this theory in my thinking I was just wanted some with more experience to let me know if I am on the correct path.

Answer 1

Thanks Fred!
that helps clear up things.  
coming to this forum really helps me in my learning, and also my peace of mind.  It always feels
good to be able to file something in your brain with enough data on it to feel comfortable.
quick question by "separate lines" what do you mean I am probably over thinking this but
when i think of separate line I think of hitting enter and having a new line but I don't think that's what you meant was it?    Or did you just mean when you use a semi colon that it created a new seperate line.  (lots of small info in your
last post there that was helpful, I am a real newbie at powershell, I just tackle some advanced topics because its in some script or cmdlet I see in my studies and I get curious, and want answers lol)