I've heard conflicting views on this one over the years and am seeking the definitive answer!
Q1: If an email is viewed in preview pane does this trigger an open?
Q2: Does this vary across different email clients?
Q3: If someone is scrolling through the emails in their inbox very quickly without actually reading preview pane will this also trigger an open?
The reason I ask is I've got some recipients for clients' newsletters where the number of opens is 40 or higher!
1) If the images are loaded, yes. All we're able to do is pick up image requests so if the image gets loaded we assume it was opened.
2) Probably not. Some people browse their email with images disabled by default, these would not register as an open.
3) Yup, I see no reason why it wouldn't. This has more to do with the particular client though since some clients cache images, others don't, others might be quicker at the request to load, while others are slower. This probably has more to do with how fast your Internet/computer is and whether or not they spent enough time scrolling through to make that request.
Something to keep in mind about high open counts is also, if they passed the email on to anyone OR gave out their webversion link, these will also register as opens for that subscriber.
Travis, would you happen to have a link which estimates/indicates statististics on preview pane usage/sizing?
As monitor sizes and resolutions continue increase, web clients continue to gain over Outlook (depending on demographics), I would think this lessens the importance of designing for the preview pane.
I realize that it may be difficult/impossible to track, but then again, I thought that about email client usage as well, which CM has done a great job at tracking for us.