/r/marketing — For MarCom advertising industry pros. Questions are accepted.

/r/AskMarketing — As the name suggests. Specifically for questions.

Content Marketing

/r/content_marketing — For discussion of content marketing. There's also /r/ContentMarketing and /r/contentmarketinguk

/r/ContentMarketingLab — Tiny subreddit about CM

/r/contentmarketingtips — CM tips

/r/ContentMarketingHacks — CM hacks

/r/VideoContentMarketing

Other Types of Marketing

/r/digital_marketing — "Digital marketing news, best practices, strategy, and learning"

/r/Emailmarketing — Email marketing

/r/digital_marketing and /r/DigitalMarketing — Both subreddits for discussing digital marketing

/r/socialmedia — A sub for professional discussions about social media

/r/SocialMediaMarketingb — Similar to the above

/r/SEO — The main subreddit for discussing SEO. There's also /r/bigseo

/r/influencermarketing — For discussing influencer marketing

/r/inbound — For discussing inbound marketing

/r/GrowthHacking — For discussing growth hacking and growth marketing

/r/dailymarketing — A daily marketing lesson