So do I have to backup the wallet more regulary than with normal transaction ?
it's an unused address taken from your keypool.
The client creates about a hundred addresses right from the start and keeps those in the keypool until they are needed/used,
so you don't really have to backup the wallet with each block you found, but more like with every hundred blocks found.
You can set your keypool-size by adding -keypool=
Yeah, know of that mecanism. I just thought mined coins would be generated under the first receive-address
Can you explain this? Why should I go to a pool now if I am finding blocks fast enough ?