Every single one of us has expertise on something.
If you're 25 years old and living in London, you know a lot about being 25 years old and living in London.
If you also work in marketing. You know a lot about being 25 in London and working in marketing.
Usually, in the age of LinkedIn, Twitter, Google+ and search engines, you can uncover more interesting things that your new members are an expert on.
When you're introducing new members, introduce them, their expertise, and invite members to ask questions about their expertise.
"One of our newest members this week is Richard Millington.
He's founder and managing director of a community consultancy.
Ask him how to get a community up and running. "
The goal is to get existing members to ask newcomers questions, not vice-versa.
This ensures newcomers feel they have expertise and can be valuable in the community.