On tonight's episode of X-Play, lead designer for Portal, Kimberly Swift, confirmed that there will be a Portal 2. This is pretty much a given as Doug Lombardi, Valve's Director of Marketing, had previously stated that "more Portal is definitely on the way." However, until now we weren't sure if this would be in the form of a direct sequel or possibly downloadable content. Well, now we know. Check out the video for the confirmation.
This is a triumph. We're making a note here: Huge Success.