That page says "btc-arbs.com IS VULNERABLE. " ?
No it is fine. That test can give a false positive when load is high.
What are you talking about? It gives part of the memory as proof :s
Just to be clear: anyone using BTC-arbs last few days should be very careful. An attacker can steal user's cookies/password as long as btc-arbs.com has this OpenSSL vulnerability.
I recommend to not use this site until this vulnerability is fixed. And well, obviously I recommend to not use them at all since months already but yeh. Will be perfect end for ponzi too "ah shit, got hacked".