Hehe... this I asked Igor a long time ago Cluster is an very specific and old computer network. I let the same word (Cluster) in English and do not translate... I think 'nobody' will see the word Cluster in your translated software anyway... I wish I had kept all Igor's emails... I could write the 'help of avast translation' here

So, Cluster means “Server”?

On the other hand, I want to know the meaning of the following statements:

avast! provides informative notes within the bodies of infected e-mails. Information may also be writen into clean messages.
Insert note into clean message