After spending a couple years working at Zillow as a software development engineer, Joyce Wu thought she had a grasp on what the biggest challenges are when it comes to the housing market. As she set out to start her own company, she learned otherwise.

Wu, 33, is the founder of Cluck, a Chrome extension that helps apartment hunters root out scam listings on Craigslist. The idea came about last fall when she started working on another project — a subletting marketplace for college students.

“We did a bunch of surveys with college students that were moving around over the summer, both looking for housing and trying to find subletters for their units,” Wu said. “The thing that they were telling me was their biggest problem wasn’t what I thought would be their biggest problem. I thought they would be complaining about price and availability, but they didn’t say that. They said they ran into scams, constantly.”