Waste nothing. Aggregate your tweets into blog entries. Aggregate blog entries into white papers. Podcast the whole thing.
Spread the wealth. If people are reluctant to contribute to the corporate blog, ask them to answer two questions on LinkedIn or Quora every week. Distribute resources to touch prospects in all relevant channels.
Customize the message to the medium. That truncated tweet looks pretty weird in a LinkedIn group, where you have space to expand. Use the unique features that each service provides.
Give to get. You build trust in social channels by being helpful. The quickest way to turn off a community is to deliver a sales pitch. Become a trusted source and the goodness will come back.
Promote everywhere. Use every relevant channel to promote new content. Invite feedback. Time your tweets to reach international prospects during their local business day.