If you live in the marginals expect US style political attack ads appearing in your youtube feed
Above is one of the most notorious US political attack ads.
Buzzfeed are reporting that
[The] Tories Bring US-Style Political Attack Adverts To The UK In Time For The Election. Paid-for political advertising on TV and radio has always been banned in the UK. But there’s no such restriction on using YouTube, and BuzzFeed News understands the Conservatives are already spending the money.
Whilst many have doubts the impact of the internet and social media on a general election campaign, this is a further example of a well resourced Conservative Party taking on a not so well resourced Labour Party unable to compete with the Tory advantage. Given the national polling indicates there is very little  between the Tories and Labour, every advantage helps.
As Buzzfeed notes, “However, it is likely that the paid-for YouTube adverts will mainly appear in the roughly 90 marginal seats which the Tories believe are key to an election victory and where they are concentrating campaign resources.”
This may also explain, why the voters think the Tories are having a better campaign so far, YouGov earlier on this week asked the following, “Taking everything into account, how good or bad an election campaign do you think the following have had so far?” Conservatives are on net +4, Greens +3, Ukip -1, Labour -30, Lib Dems -43.
All of this could explain in part, why the betting sentiment is moving towards the Tories/against Labour over on Betfair and the spreads.