Participating on the forum is quite different from other Media, I spend a lot of time on twitter but don't have as much posts as I do on the forum. The engagement, interaction and must recent feature from one of the third party providers (bot) that gives me notification took the engagement a little step further as it made the interaction more enjoyable due to the fact, I don't have to manually search for users that quoted me to respond to. Don't get why the forum doesn't have that feature yet.

OP just as others have mentioned, I don't think there's a universal approach that could guarantee you success with advertising of your new product, some will do well if you make use of online medias while others will do well either through physical promotion or traditional means that involves buying of ad slots on media networks.

It's left for the project to determine which medium would best suit its advertisment. Although just as you have highlighted, the internet has made things easier but you still have to choice among the numerous social media out there. Personally I'll go for twitter as If you're capable of hiring influencers then your product would be heard by millions of customers but still that doesn't guarantee millions of patronage.