A few months ago, I set a goal to empty my inbox. It all relates to Getting Things Done by David Allen and Inbox Zero.
To make a long story short, I had to process 10’s of thousands of emails. During this exciting work, I figured out something. When you are processing email it’s much easier if you sort by “from” instead of the default of sorting by date. This puts all of the messages from the same people together. This makes it easy to delete a block of spam all from one person (click on the first message, hold down shift, click on the last message, press delete). Additionally, it makes it much easier for reply’s because if someone has sent you multiple questions, you can read all and reply to all in one email.
To sort by from you simply click on the Column Name (in Thunderbird that’s ‘sender’, but I believe in Outlook Express it’s ‘from’).
Using this method I’m often able to process a couple hundred emails within 20-30 minutes, including answering several.