Abuse@ contacts

Hello, After a weekend of heavy spam last month, we decided to fire some reports over to the abuse contacts for each relevant IP or domain - some US/Europe based, others from more "obscure" locations. We've not had a reply from any of the reports sent over, other than some automated bounces. Each report from us contained detailed information about IP, date, headers, spam content, relevant ranges etc ... How many of you (honestly) actively manage and respond to abuse@ contact details listed in WHOIS? Or have had any luck with abuse@ contacts in the past? Who's good and who isn't? Apologies in advance if this has been around before - I'm new here. (: Gav