This was supposed to be the election when internet politics came of age, when the blogosphere and social media sites such as Twitter and Facebook had a real impact on the campaign. But it hasn't turned out like that: far from being an important player, the internet has become all but an irrelevance. So why has the web been the dog that hasn't barked?

Way back when, when Derek Draper (remember him?) was still the apple of Gordon Brown's eye and the driving force behind Labour's web strategy, he predicted that stories from the internet would dominate the news agenda for four or five days of the campaign. So far, they have done so only once, when the Labour candidate Stuart MacLennan was ditched after his obscene twitterings caused his party too much embarrassment.

But MacLennan is very much the exception, for two reasons. First, candidates have found that Twitter, as a campaigning tool, is useless. Most have so few "followers" that their tweets are irrelevant unless they say something a journalist can make a story out of – and of those followers they do have, only a small minority will be resident in their constituency. As an echo chamber, it's superb, but as a means of communicating with voters, it's not a good use of resources.

Second, MacLennan is an exception because very few people are leaving such hostages to fortune. Hardly any candidates are writing blogs during the campaign, for fear of saying something they might regret: the Conservatives are so anxious that party officials insist on vetting new material before it is posted (with good reason, as the suspension of Philip Lardner shows). And even those bloggers who are, in theory, independent have fallen into line. Sites such as ConservativeHome, which could normally be relied upon to maintain a critical distance from the official party, have openly acknowledged that they don't want to rock the boat – and I plead guilty to the same thing with my blog. The Tory blogosphere, just like its Labour and Lib Dem equivalents, has effectively neutered itself for the duration of the campaign, because no one wants to be blamed for jeopardising his party's victory.

That's not to say that the internet has been completely ineffectual. Perhaps the biggest impact has been on the parties' poster campaigns. Never again can a party produce a poster that won't be Photoshopped and spoofed. One of the best examples – and biggest gaffes – was Labour's Ashes to Ashes poster, depicting David Cameron as Gene Hunt. Within minutes of the poster being issued, Tory sites had pointed out Labour's error in portraying Cameron as a working-class folk hero; mocked-up versions were soon spreading around the internet like a virus.

There are a few other areas where the internet has had an impact. Voters find it much easier to discover information out about their candidates and party policies via Google. Then there is email, an even more powerful player: if the Conservatives win next week, it will be at least in part due to the giant database they have compiled, and the mini-databases candidates have been using to stay in touch with their electors.

Similarly, there has been progress in raising money online for candidates. A site called YouFund.me.uk has been instrumental in bringing in more than £10,000 for Anthony Calvert, the Conservative candidate seeking to castrate Ed Balls's political career in Morley & Outwood. It's doing the same for Nigel Farage's campaign to oust the Speaker in Buckingham. The Tories' own site, MyConservatives.com, allows individual candidates to raise funds in a way previously impossible – but in contrast to America, such techniques are only in their infancy. The Obama campaign used the internet to recruit and mobilise thousands of volunteers, but all three parties here have failed, in part because their efforts came too late in the electoral cycle. Obama had 100 staff on his online team: our three parties have about a dozen between them. Get real, as the Prime Minister might say.

Yet if this hasn't been the internet election, it most certainly has been the TV election. Of course, every election since the 1960s has been dominated by television, but the debates between the party leaders have turbo-charged this process. The entire news cycle is now geared to them: the pre-debate banter, the day of the debate, and then the endless post-match commentaries. The only role internet commentators have to play in this X Factor world is to try to get their reaction out as rapidly as possible, in order to shape the debate: many media outlets monitor Twitter and Facebook to see which way the wind is blowing before committing themselves to a verdict.

Will the internet recover its voice after the election? I hope so – but it is also possible that we have seen a high water mark in terms of new media's influence. Yes, the mainstream press calls on bloggers such as Tim Montgomerie, Will Straw and myself to play the role of political pundits. But the fact that so many bloggers are, effectively, professional journalists creates the impression that we're not online insurgents, breaking down the gates of the Westminster village, but just another part of the establishment. It's rather like a scene from Animal Farm: "The voters outside looked from blogger to journalist, and from journalist to blogger, and from blogger to journalist again; but already it was impossible to say which was which."