I don't know what's going on, but you're seeing a lot of YAcoin wallet stealing claims.
Do not listen to them until you hear it from someone you trust on here. The way the same people and brand new members are spreading this rumor makes it highly suspect.
Updated suspicious peoples list.
List of suspicious people -
bennybong, brewins, Aahzman, hdclover, poly, d3stroy3r.Any
Jr. member or
new account should also be viewed with suspicion.
Possible it could be a cpuminer or something aside from the yacoin-qt, again, if it is real and not a anti marketing campaign by 6 people.
UPDATE: bennybong now says his forum account was compromised and none of his coins were stolen. So he was either hacked and it's bullshit or he is backpedaling and it's bullshit.
UPDATE: Thanks to user seleme, we can see
hdclover has or has tried to gain a large amount of royalcoin.
https://bitcointalk.org/index.php?topic=201831.0Up until a few hours ago his avatar was also royalcoin. The pieces are coming together.