So not too many businesses know about a feature inside of Facebook Advertising Platform that gives you a TON of great data... It's called Facebook Audience Insights --> you can read about it--> here.
There are a TON of great features that Audience Insights will give you - including information on your competitors customers.
This video is courtesy of Kevin David - a well known Facebook Advertising Expert. You can chick out his YouTube channel here-->Here
The video should start at the 55 second mark (there is some fluff at the beginning you can skip) ... This is great information for any business that wants to attempt Facebook Advertising on their own!
Using Audience Insights, you can get aggregate and anonymous information such as:
Demographics — Age and gender, lifestyle, education, relationship status, job role and household size
Page likes — The top Pages people like in different categories, like women’s apparel or sports
Location and language — Where do people live, and what languages do they speak
Facebook usage — How frequently are people in your target audience logging onto Facebook and what device(s) they are using when they log on
Purchases activity — Past purchase behavior (i.e. heavy buyers of women’s apparel) and purchase methods (i.e., in-store, online)
And you can view this information for three different groups of people:
People on Facebook (the general Facebook audience)
People connected to your Page or event
People in Custom Audiences you’ve already created (an audience made up of your current customers)
Audience Insights is different from Page Insights because it looks at trends about your current or potential customers across Facebook, whereas Page Insights looks at the interactions with your Page (i.e., likes, comments and shares).
Hope you can use this information in your own business!