Around 40% of all primetime tweets from the UK’s 15 million monthly active Twitter users are about TV. And there are some examples where the social network can boost audiences like crazy. The Twitter effect on MTV’s Hottest from summer 2013 stunned executives – 166 million votes came in via Twitter for the show’s poll.

The MTV Music channel audience was up by 55% during transmission and there was a network-wide hike in viewers of 22% over a five-week period.

But not every TV show boasts Justin Bieber (52 million followers) or One Direction (19 million followers). So what about evidence from less Twitterfriendly programmes?

Channel 4 panel show Was It Something I Said? was often packed with Twitter-friendly stars, yet Dan Jones, creative director at Maverick TV, says the Twitterati didn’t engage because while viewers typed tweets, jokes were being missed.

He told the RTS TV Re-Tweeted event last week: “We are still experimenting [with Twitter] and we get it wrong as many times as we get it right.” In his opinion,Twitter engagement only drives ratings when a show’s talent has a collective following in excess of 10 million.

With YouTube shows, the Twitter effect can be more visible. This is because programmes can tap into Twitter’s 255 million global users and brands are happy to pay talent to tweet about YouTube shows.

Talent is clearly key to making Twitter work for TV. Ricky Gervais did a live Twitter Q&A in the hour leading up to C4’s Derek going on air, which Twitter head of partnerships Dan Biddle described as a sort of “social EPG” for the programme. In-show hashtags have also pointed viewers to character tweets.

But for docs or dramas, Twitter’s contribution can be less clear. C4’s Benefits Street caused a Twitterstorm, including death threats, but it was the wider media coverage that drove the channel’s highest audience figures for any show since 2012.

When Made In Chelsea social snob Mark-Francis thought chicken restaurant Nando’s was a posh wine bar, Nando’s was ready with its own tweets to fire into the social media world – including vouchers.

When one of the stars of C4’s Dogging Tales said Lynx deodorant was the perfect scent for ‘dogging’, Lynx tweeted a picture of an “emergency” meeting with its executives wearing ‘dogging masks’ (pictured), saying: “Crisis, what crisis?” “Lynx made light of it, which was right on brand,” says C4 head of advertising and research Martin Greenback. He believes viewing is driving tweets rather than tweets driving viewing. TV’s ad community doesn’t seem to be convinced that adding a hashtag will necessarily bring more sales.

Instead, it’s this kind of playful linking with advertisers that commercial departments want to encourage with Twitter – which could deliver real returns for the industry.