Basically nothing.

But...

In case your Cubits are on Cryptopia, you will not be able to sign a message (as the address is owned by Cryptopia).

If you want your SCIFI share, you have to move these coins to a local wallet (your address, you can sign it).

With other words, if you want some SCIFI, you should:
1) Move the QBT from Crytopia to your local wallet before February 1st.
2) Send your (local wallet) address and signed message to vampirus.
3) Wait till you received your SCIFI.
4) Send your QBT back to Cryptopia if desired.
5) Enjoy your new SCIFI.