Dylan posted his notes from David Daniels' session at the Email Insider Summit. Here are some highlights:

• How are people spending time? Email 87%, Search 70%, Research 64%, Purchase 60%, IM 37%.
  These are the top activities by online consumers, not consumers in general.
• The average person gets 274 emails a week in personal email.
• 304 emails a week at work email.
• 74% of people have 2 email accounts.
• 8% triage emails with handheld devices. (Growing)
• 18% of heavy email buyers use their mobile device to deal with emails prior to reading them in the inbox.
• 26% of the inbox is opt in marketing campaigns, the other 74% of the emails are typical personal or business correspondence.
• Why people opt out:
  53% of people unsub due to irrelevance.
  40% due to frequency
  26% unsub using this this is Spam or Junk button.

Read more here.