A cryptocurrency is a currency issued on a computer network that communicates with each other using a blockchain.
You can exchange this currency using an electronic wallet with other users.
The value of this currency depends on the number of users and the trust that users put in that currency.
The Bitshares trading platform allows you to exchange the Ventureo with other cryptocurrencies, but there are not enough users currently to exchange Ventureo.
Wikipedia article on cryptocurrency: https://en.wikipedia.org/wiki/Cryptocurrency