This is such an important part of the program that we cover in great detail in the Communication Plan at the front of the Success Guide.
The key is to incorporate the promotion of your Virtual Event Bag into your overall event communication plan, leveraging email, social media, website, mobile app (if applicable) and even onsite signage. This will bring your audience back to the bag several times over the life of the event and deliver the best results for your sponsors.
If a communication plan is done right, it is not uncommon to see 75% or more of the event audience engage with the bag.