In general, the more space you have for copy, the more readers expect to see substantiation and proof. For very short, digital ads (read: Google AdWords ad), a claimed benefit/offer followed by an implied promise of greater explanation and proof after the click is often enough to get people from the ad to the landing page. No proof required.
This is especially the case when you have to sacrifice clarity or vividness of offer to squeeze in proof elements — sometimes the trade off doesn’t work out in your favor, and it’s best to go with a stronger (yet unsubstantiated) offer.
But in general, and with other elements being equal, more proof and greater credibility is almost always better than less. And the more space you have open to provide that proof, the more the reader will grow suspicious in its absence.
So it’s worth noting that Facebook’s 135 characters of body text represents almost twice the text length of a Google Ad Words ad’s 70 character limit. So it makes sense that there would be a greater expectation for credibility cues and proof elements. And that’s where today’s Ad in the Wild comes in:
The picture certainly provides an indication that the children clothing on offer are desirable/cute/not run-of-the-mill, etc. But the copy quickly falls down on the job, promising brand names, but giving no examples. And the kicker is, when you click through to the registration page and onto the actual storefront, you find out that they really do have well-known, sought-after brands on offer (yup, I asked the wife to confirm).
And since the original ad copy only took up 68 characters, there was plenty of space to throw a few brands in as proof elements. Heck, they could even test response rates for different brands and even brands amongst demographic segments. So you’d end up with ad copy that looked something like this:
Top brand kids clothes — Mud Pie, Kate Quinn, Little Miss Tennis, and more — at up to 90% off. Hurry these are going fast!
Granted you expanded your ad copy from 68 to 124 characters, but you put quite a bit more proof into the ad.
But yet, statistically speaking, shorter ad copy does better than longer copy in Facebook ads. How is that, if adding proof elements creates a stronger ad?
It’s because ad copy can grow longer for a number of reasons, and statistically speaking, most longer ads are longer due to wordy, fluffy ad copy, and not from the inclusion of better proof elements. So a short ad that gets to the point will usually outperform a longer fluffier ad, but a short ad without proof elements will usually lose to a longer, but tightly worded ad with proof elements — and the more space the ad provides, the more this becomes the case.