The e-mail gods have answered, you can now ignore converations in Exchange 2010
Just a quick blog post I couldn’t resist! Whilst Exchange 2010 delivers a number of enterprise strength enhancements, you and your users will no doubt love the “Ignore Conversations” option. This is particularly useful when you are included in group e-mails that you could care less about!
Clients supported include Outlook 2010 and Outlook WebApp (screenshot below).