Is the dodo extinct?

Now here's an interesting question - I was of the opinion it was extinct and I know there is an expression about someone or something being as dead as a dodo and yet I wonder! Is this really just a massive piece of spin that has been perpetuated for many years?
Now you might be thinking this is a strange topic to raise but it has come about because last week I read about a bird that has made a comeback from being 'extinct' and I have just read an item in last nights Express and Star about an extinct blue butterfly.
I am beginning to wonder what extinct really means and if there is any hope for the dodo. I think the answer is watch this space!!!