Instant messenger is always a lot easier than having to sit and talk on the phone, at least for me. However, since it is so casual and just in the home, I have a tendency to get distracted and wander off. That means I have on occasion forgotten to let the person I'm talking to know that I'm afk.
With the i-Knock, it would be highly unlikely you would ever forget about a conversation or miss someone popping up while you were afk. When someone logs on, messages you or even sends you an email this little guy will hammer his head and make some noise.
You can customize him with different songs or sounds for different people, so you'll know if it's actually important. It will work with Skype, MSN and Yahoo Messenger. It also has special alerts for over 20 emoticons. Sadly, there is no word on pricing just yet.