Studios and writers agree to contract terms
According to the article, television producers have made February 15th the de facto deadline for putting the writers back and salvaging what's left of this television season. For movie studios, the deadline is seen as early March to prevent major disruption with the 2009 movie release schedule.
With that information, it's not hard to figure out why the timing of this negotiation is what it is. All the writers had to do was to wait until the bottom line of the industry started being affected and the producers caved like a house of cards (unless this compromise is some sort of ingenious plot by the AMPTP. Perhaps under the guise of negotiations they're going to trap the WGA union leaders in a room where the walls will start closing in and spikes will suddenly protrude from them).
If the talks are successful, then the strike would have ended earlier than I anticipated. I figured it would go on until late spring or summer. I presume the writers will be getting the new media percentages they're asking for, although it cost them getting membership from reality TV and animation. I wonder what other compromises were made on either side.