LONDON — Time was, investors wouldn’t look a content startup in the face. Lately, we have seen some financial energy go back in to ambitious, content-related companies. But that doesn’t change the challenging outlook, says one leading investor.

“Content as original programming remains a very hard category to invest in,” says Saul Klein of Index Ventures, the European VC firm whose portfolio has included Adconion, ChartBeat, OpenX and Songkick. That’s why Klein says content businesses supported by consumer transactions are still more investable than most ad-supported businesses.

“It’s very hard to build an ad-supported business unless you have over 50 million monthly uniques,” Klein says.

Beet.TV spoke with him at the FT Digital Media Conference. To view all our coverage of the conference, please visit this page.