Both cater to the same audience, yet one is designed as a content site and the other a community site.
HR Business content, above, is a content site. It gives full priority to giving people information. It features content in the most prominent areas of the community. Members will visit when they want information.
HR.com, below is a community site. It's designed to connected HR professionals with one another. When you visit the community you seek the contributions of other members in the most prominent positions.
If you create a content site, you're in the content business. You're not building a community, you're building an audience. You're competing against every other source of information on the topic. Loyalty levels are quite low. Average length of visit is low. Members only visit when they want information, and might not be that often. It might only be when they have a problem.
If you're building a community site, you're in the connection economy. You're competition are other social groups. People keep visiting because they feel part of a peer group. They want to know what their peers are doing. They're participating to satisfy their social needs (ego, validation, self-esteem etc...), not their information-needs. Loyalty to communities is extremely high and members visit for longer periods of time.
Both have their uses, but they're very different approaches. Pick one or the other with great care. Design your platform to be a great content site, or a great community site. Don't try to do both.
If you want to learn how to design (or redesgin) and develop your community's platform, join us for FeverBee's Community Management Masterclass at the London School of Economics of March 9th.