On StackOverflow I quite often answer questions by explaining what they should read/who they should read up on, and the names of the technologies: A simple answer might be on the lines of:

"What you are looking for is AJAX. You'll need to store your information in a database – as you mentioned PHP, you most likely will use MySQL. The javascript library jQuery has a really nice way to use AJAX, so I'd start by reading up on …, …, … and …. ."

Rather than:

"Here is the code in 3 files that i've just written without testing anything."