http://www.coindesk.com/rushwallet-delivers-fast-frictionless-login-free-bitcoin-wallets/My concerns ----> "Created in 2011, Instawallet had over 1 million accounts and was once lauded by bitcoin developers for its ability to quickly create and use bitcoin addresses. But, a 2013 hack saw it fraudulently relieved of all user funds.
Hackers were able to gain access to users’ secret URLs, which were stored online. Instawallet later replaced most users’ balances after a 90-day claims process."
Please know that RushWallet is not in any way related to Instawallet.RushWallet is more secure than InstaWallet in two specific ways:
Funds are stored client side, not server-side. Meaning that RushWallet neither holds, nor has access to users wallets or bitcoin.
The private key is stored in the URL after the hashtag. By HTTP standards, that part of the URL is not sent to the server when you make a request; it remains purely client-side, so the server never sees what any of the private keys are.
You can add an encrypted password in the URL should you so choose meaning that you'd have to enter a password every time you open your wallet.
Check out this reddit post
http://www.reddit.com/r/Bitcoin/comments/2cvr33/rushwallet_by_kryptokit_finally_an_easy_way_to/ And here's the official BitcoinTalk thread.
https://bitcointalk.org/index.php?topic=730490.0