Thanks Yannick. This is really helpful. I'm hoping Marketo will be able to build this in so we don't have to leave Marketo. I'll use these two tools until that day (hopefully) comes!
Campaign Monitor (which is a self-serve email service provider) offers a great inbox preview tool that's completely integrated into their platform. This would be great feature for Marketo to include.
OK, I saw this. But this is just allowing a view of the mobile version of a landing page against the desktop version (not even showing how the desktop version will look on mobile - you actually need to create the mobile version - which is good since responsive landing pages aren't possible). But this isn't the same thing. I think the focus of this idea here was to offer views across all browsers, all operating systems, all email clients, all devices. Like this:
I don't consider this to be the same (or even close).
I'm just concerned with it being marked "Already have it (partially)", that it won't get the attention for future enhancements.
Adam - are you saying that your original idea was more in line what Marketo did with the mobile landing page capabilitity, or were you referring to a capability similar to what Litmus, Email on Acid (my screenshot) and other ESPs provide? If it's the latter, I'd hate to see these votes go to waste.