Smartlands account is a Stellar network (blockchain) account with multisig structure.
Initially any account in the Stellar network is controlled by a private key of an account. The Stellar network provides an ability to add additional signers (private keys), set their weight and set certain threshold levels required for transactions to happen. In order to perform any action from an account, total weight of all signers should be above the threshold level.
In Smartlands accounts the weight of private key controlled by user has a weight of 1, the private key controlled by Smartlands platform has weight of 2, while threshold level for regular operations is 3. It means that a transaction should be signed by both.
Additionally there is a recovery signer. It is a hash of a transaction to add a signer with weight of 3. The private key that could be added as a signer to recover your account is stored on Ledger hardware wallet. Moreover, there is an additional layer of protection that prevents any security threads.
You can find detailed description of multisig accounts on the Stellar network here.