Deja Vu

So really, what is it?
Does it exist?
According to "The Matrix" it exists.
Is it a man-made explanation, or do we really have a sense of recurrence?
I only bring this up because I was editing my blog, as you may have noticed, and I had the strange sensation that I was experiencing these same thoughts and actions before. And this is not the first time either.

Seriously, what do you think?

Side note: I did not see the movie "Deja Vu" staring Denzel Washington, nor do I have a strong desire to see it.