1) Digital marketing involves promoting products and services through digital channels like the internet, mobile, and social media instead of traditional channels like TV, print, and radio.
2) Marketers have had to adjust their strategies to deal with issues like message clutter, overwhelmed consumers who ignore ads, and new technologies that allow consumers to skip ads.
3) Common digital marketing strategies discussed in the document include internet marketing, mobile marketing, social media marketing, viral marketing, and using apps, consumer reviews, and events/sponsorships.