Whether leaving the EU will be a positive or a negative for email marketing is open to question. Whilst most commentators favour the latter, there are no certainties.
What we do know is that there will be a period, up to the exit and for some time afterwards, where there will be volatility in the markets, with the pound likely to suffer against the Euro. Long term consequence will not be known until negotiations are concluded.
All one can do is guess, although some things are more likely than others. For instance, data protection regulations will most likely be unchanged and it is probable that any modifications made to systems in the EU with regards to use and security of our email marketing lists will be incorporated as a matter of course. To put it briefly, you will still need to prepare for the GDPR.
A variation on the Norwegian Option seems to be the favoured exit strategy at the moment, although much will depend on whom the next Tory leader will be. May seems to favour it while a recent speech, post vote, by Boris Johnson referred to it, albeit rather obliquely. In essence it could be more or less status quo, including the free movement of people, and the only thing to suffer is the UK’s influence on the government of the EU.
The main problem for email marketing, and all domestic businesses, is the uncertainty. Much of the population might not consider this as a time to splash out on an expensive cruise or to be tempted by that new suite.
On top of that there is the political infighting that has already started. There is little more likely to spook the markets and those holding the purse strings. Both main parties have leadership problems to resolve, the Tories opting for a new PM, with all the spats that that entails, and Labour challenging their leader.
May you live in interesting times is very apt at the moment. Your short term planning might benefit from keeping your options open so you can take advantage of any opportunity although without committing yourself long term. The current plunge of Sterling against the dollar is probably temporary, but who knows?
No one at the moment it seems.