Thousands of youngsters looking for reviews on the latest teen fiction are logging on to a website created by two boys from Cornwall.
A big influence ((C) Photopoint - http://www.sammorganmoore.com)
Chris Cross, 15, and brother Tim, 14, set up cool-reads.com when they got fed up with not being able to find decent reviews of children's books.
The pair use 10 to 15-year-olds to review books aimed at the same age group.
Now the pair, from Saltash, are becoming hot property for their views on the site, which gets about one million hits a month.
When BBC Radio 4's Today programme wanted someone to review the latest Harry Potter saga, they chose the Cross brothers.
And when Elaine McQuaid, marketing director of Puffin Books, wants to see how their books are going down in teenage-land, she logs onto cool-reads.
Children don't pull any punches
Elaine McQuaid, Puffin Books
She said: "For teenagers, that word-of-mouth thing is incredibly important. It's the biggest influence on teenager readers.
"Children writing reviews is absolutely invaluable. They don't pull any punches."
Books are rated with star system, from "best avoided" to "really good stuff".
Chris said: "Tim reads more than I do. He will probably read 10 books a week, whereas I might read only six or seven.
"We try to catch him out by asking him questions, but he seems to have read them completely."
Tim said: "With schoolwork it gets quite hard to read a lot, but I have been known to read about 16 a week in the holidays - but they were all quite small."
Reviews come mainly from the brothers, but they also come in from around the world.
The brothers also have five "star reviewers", all girls.
Chris said: "Girls tend to read more instead of going outside skateboarding.
"Generally the reviews that the girls do are longer and they give a better idea of the story and the characters.
"And they probably justify the rating they give it better than most boys do.
"For instance, we get reviews from boys who say this is a great book and give it five stars, but they don't say why it's a great book."
And what did they think of the latest bestseller, Harry Potter and the Order of the Phoenix?
Four stars, or "really good stuff".