It's very easy to filter for viewing (both in the UI and in Internet Explorer - when something goes wrong you're going to want the messages to investigate the cause. At the bottom of the screen, select the check box next to the blue "i" in the bubble.
You can also use the Log.LockEvents method method in your scripts to avoid posting event messages to the Test Log: The method has a parameter that specifies the number of event messages that will be kept in the buffer and it is set to 20 by default. If an error occurs, these messages are posted to the Log. Please read the "Log.LockEvents" Help topic to learn more about this method.
In TC3, if you ask to "View results in IE" you'll get a list of all the test results. The rightmost column says "details" and that's a link that opens up the log of that test.
There are check boxes right above those details that will allow you to filter the view. (I'll see if I can post a pic.. Doesn't look like it (no attachments apparently) - but they look similar to the checkboxes you see on the "Test Log" tab.