Pinterest introduces advertising in the form of 'promoted pins'

Pinterest, the pinboard-style social network beloved of crafters and cooks, is to introduce advertising in the form of "promoted pins".

The site's chief executive and co-founder, Ben Silbermann, announced the change on Thursday.

"For our first test, we'll promote a few pins in search results and category feeds," he wrote in a blogpost. "For example, a pin for a Darth Vader outfit from a costume shop might be promoted in a search for 'halloween'."

Silbermann was keen to emphasise that the promotions would be "tasteful… transparent… [and] relevant", and the system would change over time based on user feedback.

At present, the company is offering the trial scheme to selected advertisers for free.

"We want to see how things go and, more than anything, hear what you think," said Silbermann's post.

"Nobody's paying for anything yet - we want to see how things go and, more than anything, hear what you think."

The demographic of Pinterest's community is particularly appealing to advertisers, showing strong support amongst women and people with university-level education.

Promoted pins are not the first attempt at monetisation by Pinterest. The site collects 'affiliate' payments on purchases made through outward-bound links.

That strategy led to a minor controversy in early 2012, after users complained that it wasn't clear enough that Pinterest was modifying their links to insert the affiliate codes.

"We'll always let you know if someone paid for what you see, or where you see it," wrote Silbermann, emphasising the transparency of the new promoted pins tool.

Pinterest has faced new competition in recent months from Fancy, a New York startup with a similar focus on curating images of desirable items.

In July, Fancy received funding worth $53m (£33m), giving it a valuation of $600m (£374m). That includes investment from Will Smith and American Express, but doesn't bring its valuation close to Pinterest, whose most recent funding round secured it $200m (£125m) and valued it at $2.5bn (£1.56bn).