Lets all take notice today from what happened to VeriCoin (which I do not own) on Mintpal.

If you are not actively trading your CINNI, then there is no reason to keep it all on an exchange. Stake your CINNI and earn PoS interest instead!

In case you are not sure what issue I am referring to:

https://support.mintpal.com/index.php?module=announce&sec=view&id=17
http://www.vericoin.info/downloads/Statement.pdf

The network is more secure when many people are staking instead of a large percentage of a currency being held in one place (in this case about 30% or VRC was held at Mintpal).