Inputs.io is a free Bitcoin eWallet that leverages it's own off chain payment network. Inputs is one of the most secure web wallets on the market, with two factor authentication, location based email confirmation, client sided hashing, and a setup that prevents the hack of Bitcoins even if the web server was compromised.
Users do not need to download the blockchain to create a wallet, which makes Bitcoin easier to use. Transactions are mixed by default with no fee to provide anonymity. However, the site doesn't leverage client side cryptography and doesn't allow it's users to export their private keys. Take caution when using any web wallet service.
Inputs.io also offers an extensive API for using the off-chain payment network.
Currently, Inputs.io is supported by the following sites:
Inputs.io is also a Bitcoin Foundation Silver member.