When you are asked by an event organiser to speak, their decision is made as there is a perceived opportunity to have you (the expert) attract and engage a target audience. For the organiser, the objective is to sell more tickets, while you reciprocate with your time and energy to have an audience listening to your perspectives for that moment in time. If both you and the organiser are to be successful, it is essential that the audience (who are paying the bills) get good value for their money from high value, expert perspectives that are in some way useful to their professional lives.
Taking this online, your content must have the same impact. Whether the distribution be across via newsletters, 1-2-1 email, social media or your website, you are speaking to the same people as in that physical audience.
GDPR is forcing (quite rightly) organisations to ensure their mailing lists are agreeing to receiving content. ICO have some good guidelines here. All of this is actually very positive and in the long run those that get this right will own the captive audience for their industry.
The concept of quality digital content for the right people is not new, inbound marketing has been around for a long time but now it is going to become ever more important to have the highest quality content available for your audience and this can only come from the niche subject matter expert. There is a massive opportunity for marketers to be the first to adapt to these changes, ahead of May 2018 so their firm in a crowded market is seen as the 'go-to' and authority.
There is simply not enough time for B2B buyers to be reading multiple email channels so owning this first will be important and another consideration is leveraging your experts' own digital networks to drive traffic to your site.
There is very good research by LinkedIn and Edelman here about the characteristics and delivery of this content here.