NOTE: This app is no longer maintained (its source repo was archived).

Wallet that uses multisig to improve security (adding 2 factor for instance or limits) and Hierarchical Deterministic addresses (see BIP32).

It offers the advantages of a web wallet:

Ubiquitously available

Social/email/sms integration

Two factor authentication

Transactions limits/restrictions

Greenaddress instant transaction

and the advantages of a local software wallet like Electrum:

Mnemonic seed backup once and forget

Your private keys are never on the server, not even encrypted

No long wait to synchronize the full client with the Bitcoin blockchain

See their website and their FAQ for more information.

Supports NFC for login and QR code scanning for login and transactions.