I recently posted this question to get the opinions of other programmers. To me there really isn't a definite answer so wouldn't that make it an appropriate question for this site?
You're kinda straddling the line between SO-appropriate and P.SE appropriate...
How to ask for a code review
There's nothing wrong with asking SO for feedback on some code, provided you've put some effort into it.
Is there anything wrong with this code?
<massive code dump>
Are there problems with passing a callback to a constructor to allow for lazy initialization?
Description of technique used in code
Brief code snippet(s) illustrating only relevant techniques
You've managed to get about half-way on this: you're asking for feedback on the practicality of a specific technique, but rather than describing the technique and your motivations for using it, you've just dumped the code with a few hints as to what it does. Your question starts out sounding like it might be P.SE-appropriate ("what would you think upon seeing this signature?") but then delves into meatier implementation details (more of a SO thing).
Also, your title is unacceptably vague.
Decide what you want the answers to look like.
If you're questioning the readability/maintainability of the code (whether the implementation, or the client code) then ask about that - P.SE is a reasonable location.
If you're concerned that the implementation itself fails in some way (error handling, efficiency, unforeseen pitfalls involving the callback referencing disposed data) then be clear about why and how you're using it, and ask on SO. Note that you'll probably get comments on readability/maintainability as well, 'cause SO users are helpful like that.