As a person, who wants to build stronger long-term relationships with other people in their professional network one of the best ways to do this is by helping them with what they may need help with at the moment, without expecting anything in return. More of a “philanthropic” investment in your karma, when the quality of the relationships is more important than the number of your (meaningless) connections.
A platform (don’t want to say social network =) where people can share publicly or privately what their current needs are (e.g. find a new job, find a new client for their service, find a professional for a need, find a volunteer, etc.). As a part of this platform, you can see the current needs of your network on your “radar” and help them with that they may be needing help with. For example, connect a business owner who needs help with their social media campaign with another connection of yours who can help them with this campaign. As a result, they both help each other and get value out of this new connection. And you get good karma points =)