Ask members to answer these two questions when they join your online community.
1) What do you have to offer the community? This lets members identify characteristics and skills their proud of. People like to feel appreciated for their assets. Give them a means to do so. Ask for their expertise in these fields, start conversations about them, launch projects using them.
2) What do you want to achieve in this community? This less subtle question lets you understand what a member wants from the community. Now you know what your members want and you can match it up to the skills your community has.
Set them as profile questions if you can. Members will identify with others easier once they know their skills and motivations.