Why our politicians are a step behind the states

If you were to ask why Barrack Obama succeded where his fellow democrat John Kerry had failed , and won the 2008 US Predsidential Elections you would have a simple answer. Because he used (alongside the support of his staff) social media to connect with the younger demographic.
Watching "Ask the Chancellors" on Channel 4 last night was interesting and engaging- at last count by politcal social media tracking tool Tweet Minister had tweets for the hour the programme was broadcast at 12'500 or 4 tweets a second/240 tweets a minute. I decided to see how easy it was to "connect" with political parties on social media. Labour came in the bottom of the polls on Facebook with Just over 9'000 facebook fans, Liberal Democrats a little better with 9'585 fans and Conservatives led the major three parties by having 28'000 facebook fans.
If I was David Cameron though I wouldn't be pulling out the bunting yet as in social media terms thats very poor- The Facebook group "Jeremy Clarkson for Prime Minister" has in excess of half a million members.
It seems after further investigation that especially on a local level the big parties aren't very interested in connecting with you on social media. I'm just curious to know why they feel they are safe to not communicate with people through this medium.
If I had been responsible for the PR on any of the three chancellors last night I would have made damn sure I was tweeting and posting and spreading awareness of party policies and ways to get involved.
Lets see if they up their game over the next six weeks