Once upon a time, the World Series provided the foreplay for major deals as general managers would gather at the Fall Classic, run into each another, and start the ball rolling. The World Series is no longer that place, replaced by the GM meetings, which begin about week after the World Series, usually at a warm location (this year here in Orlando), about a month ahead of the winter meetings, where some of the deals talked about here are consummated.
Agents peek in and out at these meetings, holding private sessions with teams interested in their client. By now, most teams have made contact with the agents of top free agents in which they have interest. The GM meetings are normally where the next phase occurs. You may even hear about an offer being made to a free agent, or trade talks in their preliminary stages.