What does the "Boost" lightning bolt button do?

One-click Boosting for Articles :

Clicking on the Boost lighting bolt next to an article means that the article will be added to every subscriber’s newsletter. The AI will still choose the placement of the article for each subscriber but this will guarantee that the article will be included in the email. 

Clicking on the Boost lighting bolt next to a source means that any article(s) from this source in your upcoming content pool will be added to every subscriber's newsletter. Similarly to the article boost, the AI will still choose the placement. 

Double-click aka SUPER Boosting for Articles: 

Double clicking on the Boost lighting bolt next to an article means that the article will be added to every subscriber’s newsletter as the first article. 

Double clicking on the Boost lighting bolt next to a source means that any article(s) from this source in your upcoming content pool will be added to every subscriber's newsletter first article. If a Super Boosted source publishes multiple articles, one of those will be chosen by the AI for the first slot and the others will follow.

Boosted Sources mean that ALL articles pulled in from that source will be sent to all of your subscribers in their newsletters. We do not recommend boosting a source that publishes lots of articles. You may only want to boost an internal source that you are sure you always want to feature. For example, your blog that produces one new article a week.