An important part of your communication strategy is to show that you are listening and acting upon the best ideas from the community.There are a couple ways you can do this.

• With the new expert icons your moderators will stand out and provide an official voice. They can join the conversation by validating ideas, asking follow-up questions, or providing updates.
• You can use the new status tags to flag ideas as under consideration, coming soon, or delivered. This provides the community an easy way to sort ideas and see all the things that are being acted upon.
• Some companies choose to run a blog along side the ideas application. With a blog you can create a date ordered narrative about things taking place within the community.
• To draw users back to the site, it's also a good idea to create a quarterly email newsletter to community progress and highlight interesting ideas.

Starbucks is the model example having implement each of these feedback channels. By sending out emails like the one below and starting a dialog with their customers, they create new evangelists  who in turn promote the site and the Starbucks brand. It's a virtuous cycle which leads to a vibrant, successful community.

Also See... Salesforce Ideas Process Map