Keyboard Text Replacement

I have tried posting on every Mac Forum I can think of without any solutions to my problem being offered. Can anyone here help please?
I am very puzzled. On my new iMac running Mavericks, I cannot get text replacement to work.

On my iPad or iPhone I can set up keys for text that will automatically get inserted in a field or on a document when those keys are pressed. For example using @@ (which is not likely to be a normal set of key strokes) I can immediately get the keys to expand and insert my email address.

I can set these keys and texts up on the iMac (preferences/keyboard/text) but nothing I do seems to allow me to type @@ and get my email address (for example) anywhere - even in a plain text document. What am I doing wrong or missing? This faciity works exactly as intended on my iPhone and iPad so why not on the iMac Desktop?

different operating system

Sorry if it sounds rude but that's not really very helpful. I appreciate that an iMac is not the same as an iPad but why does Mavericks offer the facility then and why are any shortcuts I create in my iPad copied across to iMac? No good if you can't use them and that was the question.

You'll have to ask Apple's software engineers. It is what it is. Why? Don't know.

In a Unix desktop OS, the auto correct / character substitution function was traditionally application-specific, and rightly so, in my opinion - not all plain text ones will be appropriate for a formal letter in Writer / Pages, etc.

However, what you want to achieve is not impossible, by any means, just takes a bit more effort, e.g.:

• In Mail - go to Edit | Substitutions and make sure the Text Replacement option is checked
• In Notes, Reminders, Safari, Calendar, Contacts - works automatically
• In OpenOffice - go to Tools | AutoCorrect Options and set the desired substitutions once more

and so on ...

The above, of course, assuming you've already setup your substitutions in Preferences | Keyboard | Text, just as you mentioned.

Just to test this, I added @@ as a keyboard shortcut and put my email address as the fill-in. It worked exactly as expected: @@ plus a space filled out the email address. I'm running Mavericks.