I think different things work for different folks/teams/functions. Having said that, I am listing out a few things that have worked for us:
Seeding the group with content that will be of interest to the community members: e.g., if it's a project team, it may be helpful to have all project related documents, trackers, presentations, specs, training materials, etc., to be uploaded into the community space prior to opening it up to the members. Enlisting the help of a couple of evangelists from the team is good practice. This way, the community will find all that they need in one place, will find it easy to on-board new project members (if needed), and will begin to perceive the space as their one-stop shop for all project work.
Start a couple of discussions relevant to the community members: Part of seeding the community is also to demonstrate to community members how they can engage in the community. Asking questions/starting discussions is one great way of doing it.
Encourage participation by highlighting member contribution: Acknowledging the efforts of those who take their time to contribute is a great way to boost interaction.
I would love to know if you’ve tried any of these and how did they help.
Here are some of the barriers ive seen & some of the things ive done to counter:
You may already have done this , but I find that in my company a little training goes a long way. I find people perceive that they don't have the time to learn something new & think it will take too long to learn their way around Jive. For these people, its not anout the business use, but about the learning. But a one hour class about navigation and adding content seems to help a lot of people. Once they understand basic functionality, they start to see business uses more clearly.
For the people who are worried that it will be cumbersome, I try to equate it to FB or other social apps that thy are already using and make parallels there.
Some people I encounter site the fear that folks will be unprofessional, and therefore they stay away. I ( nicely) ask them how many times they've been unprofessional via email, phone or IM-- of course the answer is never. I then ( nicely) ask, "then why would you do that on Jive?" sometimes this is all it takes to refocus the individual so that s/ he realizes it is an unfounded fear. I also point out how our " report abuse" system works, and drive home the point that in the 2 yrs I've been doing this, we've never had anything abusive reported.
Hope this helps!