I have noticed just today that there is a banner that will pop up now and again when I am on SU.
Is this something new?
A suggestion for this "feature", inspired by the StackOverflowSort (XKCD).
Grab some keywords from the user's question, search on SO (or whatever site context), take the top question with an accepted answer, and return the first/last/random sentence from the answer.
Though this might have the tragic byproduct of the feature actually being... useful. gasp
It's an April Fools' joke. The "expert" is simply a basic AI that repeats a select set of words you write, inserting them into a set of possible responses in order to form a reasonably coherent (grammatically speaking) statement.
See this Meta Stack Overflow question: What is "chat with an expert"?