MetaMask is a free extension for Chrome, Firefox and Opera, please navigate to one of the below:
Chrome Extension Page
Log out when you don't use the wallet
Make sure that you are on the Main Network (top left corver green button)
Never give your Private key to anyone, only the Public key (your receiving address)
Always check that the website is https://myetherwallet.com and green URL bar has MYETHERWALLET INC.
When registering new address, please make sure you are on the ETH network (Etherscan.io) and save your access keys to the location that no one has access to, but where it won't be lost.
Adding your address to MetaMask can be done through the import of the Private Key or JSON file into the MetaMask
Secure Oracles POA Network is a fork of the Ethereum blockchain with faster and cheaper transactions. They have raised 12,500,000 for their ICO last year and there already were few successful ICOs that run on this platform.
We use POA Network for our Tokens crowdsale, but all of the details, addresses and contracts can also be seen on Etherscan.io