Digital channels including Facebook, blogs and political websites had the greatest impact on traditionally apathetic young voters aged 18 to 24. Almost a third said online content had significantly influenced their voting decision.
Despite the hype around Twitter's potential influence in the run up to the election, only five per cent of UK voters claim to have read any political content on the site.
Among voters aged 18 to 24, Facebook was far more influential, with over a third (36 per cent) reading political information from the site compared with only 13 per cent on Twitter.
Diffusion MD Daljit Bhurji said: 'This was not the "digital election" some had predicted but it certainly was a digital election, with online campaigning making an impact with the majority of the public.
'Whether in five years or in five months, the next general election is likely to see an even greater proportion of campaign war chests invested in online channels.'
YouGov surveyed 2,300 people on behalf of digital PR agency Diffusion.