How much do newspapers really influence us ?

After reading over the weekend that David Milliband, one of the potential labour leaders has now gained the backing of the Times to add to his collection of the Observer and the Daily Mirror.

i would like to ask you does having the backing of a paper really matter that much. Ultimatly the voters decide- the Labour members in this situation. Would people vote for a particular party or polititian based on the support o a newspaper.

What similarities are there to a Union reccomending its members vote for a particular candidate. Should a newspaper even be allowed to endorse a candidate. Is it unfair to the other contenders.

During the last election one of Britains biggest newspapers the Sun chose to back the conservatives, although didnt actually win out right as much as they would dispute this i feel this did have a big influence and the story of them backing the tories was big at the time.

SO does it matter if a paper backs someone and if so, how much influence do the media and the papers in particular have over its readers these days ?