Yammer , a twitter-like service for closed groups, continues to add new features that I wish Twitter would implement as well. In the last day or so they added a simple notification for unread messages that syncs across the many ways users can access the service (mobile, AIR, browser). The notification is available through the Yammer API as well. Twitter needs something like this. Various Twitter clients built by third party services try to do it on their own, but without the feature at the API level it only works if you access Twitter just from that client. Yammer has consistently pushed new and useful features quickly to users. If you don't use Yammer at your business, you should. We've been fans of the service since launching at TechCrunch50 in 2008. It has replaced email for most of our in-office communication. And the service is very reliable, other than the occasional service outage while their CEO David Sacks is off playing poker in Vegas . The company is also getting more serious about the Android platform. Until recently the only Yammer app for Android was created by Nullwire. Yammer acquired the product from Nullwire and will now develop it in-house. You can download it here .