Media: All about ... TV channels' winter schedules.

Broadcasters are showing their hands to advertisers.

It is the time of the year when the major broadcasters reveal their winter schedules. With the erosion of mass audiences, as multi-channel TV takes hold and viewers migrate to alternative media such as the internet, the winter schedule is the one card broadcasters still have left up their sleeves.

That is especially true for ITV1. which revealed its line-up this week, the last of the major commercial broadcasters to do so. The ability to build mass audiences is the only point of difference between ITV1 and its commercial rivals, and the winter schedule is the backbone of its calendar year, when TV viewing is at its highest. For advertisers such as Pepsi, O2, Barclays and Ford, it is a critical part of any schedule, allowing the big brand advertisers the chance to show off their wares in front of large audiences.

Although mass audiences no longer have the potency they once did, the broadcasters still attach a great deal of importance to their winter line-ups. Their sales teams invest many man-hours at this time of the year presenting to media agencies and advertisers.

Broadcasters have not always embarked on this annual schmooze-fest with the market. The ritual dates back to the late 80s and early 90s, when the newly independent Channel 4 had yet to gain momentum. Advertisers were paying artificially high rates because of a combination of inflation and ITV's monopoly. Also, many wanted to see a fifth terrestrial TV channel emerge to smash ITV's dominance of the market, but that was a long way from happening.

With ITV under pressure to produce more drama and fewer soaps, and advertisers worried that it took a downmarket, mass-market approach, the channel resolved to become more advertiser-friendly, and so the concept of upfront presentations was born.

The idea comes from the US, where there is a greater tradition of collaboration between advertisers and TV programme-makers. However, some have questioned the value of the presentations in an increasingly commoditised market. Unlike the US, where advertisers commit upfront to specific shows, sometimes as early as spring, media buyers in the UK buy a ratings package based on the station average price.