Thanks for the response. I indeed label them Spam. The problem is Gmail does not then automatically block or filter out new such messages in future (I guess the

Thanks for the response. I indeed label them Spam. The problem is Gmail does not then automatically block or filter out new such messages in future (I guess they have some threshold for number of reports or something). Also looked at writing a script to implement a black list myself - however gmail email settings API only available for Google Apps.