I like Compete. I use their free analytics services and don’t mind receiving their marketing emails about their premium offerings.
Here’s an email I received from them today, though. Doh!

I don't think this is the core message which Compete wants to convey
The problem, of course, is that gmail (like many email platforms) suppressed Compete’s embedded images by default. It was only after I clicked to enable images in the email that Compete’s intended message appeared:

That's more like it
The lesson of course is that you should prepare for this and know in advance how your email will look with the images suppressed. It’s sort of like those classic Mad Magazine “fold-in” puzzles.