A study conducted by Marketing Brew and an API called Pushshift resulted in some pretty odd findings regarding which subreddits allowed ads and which ones didn’t. 

The findings. The results are based on the API pulling data from the top 2,500 most popular subreddits. They show that despite spending the last decade trying to address brand-safety concerns, their actual approach is more cautious, which makes the platform seem unpredictable and inconsistent. 

Where Reddit doesn’t allow advertising. These are popular subreddits where Reddit doesn’t allow ads. 

• r/mileycyrus
• r/mensrights
• r/daftpunk
• r/floridaman
• r/mensrights  
• r/mdma
• r/islam
• r/israel
• r/redhotchilipeppers
• r/depression 
• r/archerfx (a community dedicated to a popular animated television show)
• r/ska
• r/stopsmoking

Where Reddit does allow ads. Some subreddits that were allowed to run ads included political and alcohol topics.

• r/alcohol
• r/crypto
• r/religion
• r/politics
• r/neutralpolitics
• r/ukpolitics
• r/canadianpolitics

Some ads. Weirdly enough, these subreddits were labeled as sometimes allowing ads. 

• r/americanpolitics
• r/internationalpolitics
• r/liberal
• r/conservative

What Reddit says. Reddit spokesperson Amanda Geraldo said that every new subreddit is labeled no_ads until it goes through a “manual human review” to gauge if it’s considered safe. She also said subreddits labeled as some_ads require advertisers to “opt-in or opt-out of advertising” and are considered “expanded inventory.”

Why we care. Reddit is expected to surpass $522 million in ad spend by 2023. For perspective, Twitter is expected to bring in $5.58 billion this year. Even though they’re on the smaller end of the spectrum as far as ad platforms go, there’s still a lot of potential upside. If you’re an advertiser looking to run ads on Reddit, be aware of where your ads may or may not be allowed.