How does Datapeople categorize Inbound sources?

How does Datapeople define what is a paid vs free inbound source?  

In the Inbound report:

• Paid job boards are those that require payment (via subscription, seat licenses, or by job posting)
• Free job boards are those that do not require payment (ex. LinkedIn Limited Listings). 
• Other Inbound sources include sources that are not exactly job boards, such as your Career Page, Social Media and Events

How does Datapeople define what is a niche vs general inbound source?  

In the Inbound report:

• Niche job boards are those that target a specific industry or population.
  • Examples of this include StackOverflow, Careers in Food, Women who Code. 
• General job boards might have some localization in terms of location (e.g. Naukri is more popular in India) but aren’t targeted in terms of industry or vertical.
  • Some examples are LinkedIn, Indeed, Monster, CareerBuilder, Naukri. 
• Other Inbound sources include sources that are not exactly job boards, such as your Career Page, Social Media and Events