There have been some notable hits and misses by celebrities, movie stars and a certain POTUS (yes, that POTUS) on Reddit. When it comes to gratuitous self-promotion, celebrities and artists use Reddit as a fan interaction medium – connecting on a deeper level with the people who support them. Of course there are those who are less than genial and end up receiving the ire of a community. It's not just about celebrities however: game development studios and tech startups have received their fair share of publicity on Reddit.
Aside from being a potential PR tool, there are other ways to use Reddit outside gratuitous self-promotion! Woah.
So...how do you use Reddit beyond said gratuitous self-promotion?
Segmentation: The great thing about Reddit is that all the segmentation is already done for you: that's what subreddits are for! People on Reddit are already segmented based on their interests, so it's really just a matter of zoning in on the subreddits you think your audience is interested in
Focus groups: /r/askreddit is one giant cacophonous focus group on the Internet where you can ask questions about pretty much everything under the sun. The trick is not to ask directly about the brand ("What do you think about McDonalds"), but to focus on topics around it ("What kind of fast food do you wish never gets served?").
Market research: Rarely will you have the opportunity to observe your target market in such close proximity. Subreddits yield a vault of qualitative data market researchers can use to influence how they further gather data. They also open you up to a whole world of valuable consumer insight. While bigger brands have their own subreddits run by brand loyalists (see: /r/apple, /r/subaru, /r/windows etc.), you can see what people are saying around topics related to your brand. If you're fitness-related start-up you can subscribe to /r/advancedfitness or /r/running to keep abreast on any trends in the community. Anonymity is highly valued on Reddit and because of this you can expect a higher degree of accuracy and honesty with people's responses.