I like about the ad is the way it talks up the usefulness of email as a method for making businesses run faster and better and it most likely was and still is. Something I've noticed however, is that the lack of email addresses. The ad talks about sending mail from terminal to terminal(s), but makes no mention of whether or not email address existed. Wikipedia doesn't have an answer, but I think addresses probably didn't exist back then. It's possible that each terminal had it's own ID and sending an email to one worked similar to a modern email address.
I can imagine what it must have been like back then. A person working for a company needed to run something by someone in another department (maybe the head of a design team to the head of the accounting department) and instead of picking up the phone or physically going to that person's office (if that was even possible), they would pop off an email instead. The biggest advantage I see with that is that you wouldn't need to have all of your employees and departments in one building. I think a lot of tech companies nowadays have their headquarters set up in a campus format with multiple buildings as opposed to a single skyscraper. Hell, you wouldn't even need to have them all in the same city. Distributive business model?
I also like the way the ad is drawn. The way the artist set the desk and office up, it looks like what an one back then probably would have looked. It also presents an interesting contrast with the ad's pronouncement of the "Office of the Future". He has a stapler and a tape dispenser, both of which would likely be rendered obsolete in the Office of the Future and eventually in real life, since physical paperwork is probably dwindling in the age of tablets and touch screens. I don't know whether they still use corded phones (though, all the TV shows and movies seem to think so), but that one right there is outdated as all hell. The two (three?) picture frames are a nice touch, adding a touch of personability to the businessman, something we don't see much in popular culture or real life. Is that an ashtray in front of the double picture frame, though? That's how you can tell this ad is old - that people were allowed to smoke inside an office building instead of outside.
All in all, it's a nice snapshot of what a typical 1970s office probably looked like and that fits in nicely with my interest in the 70s tech industry.