However, it's interesting to see that with the latest figures from AA/Warc for third-quarter 2018 -- the first full quarter of GDPR applying -- the prediction seems way off the mark, other than in radio and outdoor.
As ever, the big winner is online advertising, which grew 12% compared to the third quarter of the year before. Mobile in particular and yet again is the big star, leaping 23%.
Print is, once again, a loser. Clearly, GDPR did not send advertisers competing for above-the-line pages in the national media, which dropped 7% between third-quarter 2017 and third-quarter 2018. Local media was also down, by 5.3%.
Perhaps one of the biggest surprises was direct mail. It dropped a massive 14% in third-quarter 2018. The first full quarter that GDPR applied, advertisers decided to spend less on letters.
I'm assuming that door drops, aka "junk mail," is included in this figure? It's a fair assumption because Royal Mail had predicted that door drops would soar after GDPR because they do not feature an address and, if they do feature part of an address, they are typically marked for 'the occupier' or "the bill payer."
Today's Royal Mail figures show letter volumes were down 8% and revenue from letters fell 6% in the nine months up to December 2018. They are expecting the decline to continue, and Sky News reveals GDPR is being blamed alongside uncertainty around Brexit.
So there is a question mark around the decline occurring in addressed or non-addressed mail, but for a brand that was bold in predicting the benefits of the doormat over the inbox before May, it's quite a reversal of fortune.
What actually happened was that internet marketing increased 12% in the same first quarter when GDPR applied fully.
Perhaps the most alarming figure is that not even GDPR could help television to avoid flatlining. It was down just 0.1% in third-quarter 2018. This was one of the channels tipped to be a massive winner from companies that were concerned about email lists getting smaller and question marks hanging over how digital display is traded under new privacy rules.
The same goes for cinema. It was supposed to thrive under tighter privacy rules, but it actually declined 8% in the third quarter of last year.
Elsewhere, it was good news for radio -- up 5% -- and outdoor, which was up 7%. These channels are enjoying a digital renaissance which appears to have played well with anyone seeking to go above the line while the dust from GDPR settled.
With these two channels that were riding a digital wave aside, the above-the-line boost that many predicted after GDPR just didn't happen. TV was still flatlining in the first quarter of GDPR fully applied; print was down, as usual; and direct mail plummeted alongside -- rather surprisingly -- cinema.
It is possible that digital advertising, where the big budget growth is still occurring, may have some bad GDPR news, should it turn out that programmatic trading is a little too murky for regulators or the duopoly is taken to task over the post GDPR positions, as has happened with CNIL's 50m Euro Google fine.
However, right here and now we can say that GDPR raised serious question marks about whether money would continue to flow at faster rates into digital display. The outcome was that it did.
There were suggestions that tv, cinema and direct mail would prosper, but they did not.
The predictions were not true. GDPR has not held back the digital marketing tide.