Erin Cadigan / Shutterstock.com SAN FRANCISCO — Wouldn’t it be nice to know if someone wanted to sell a home before he or she did? Real estate agencies might never be able to truly predict the future, but thanks to advances in predictive analytics and advanced data, they’re getting pretty close. Accoridng to Cary Sylvester, vice president of industry development at Keller Williams Realty International in Austin, the biggest challenge is taking all of that data and figuring out how to effectively use it. “Insight is the difference between having a lot of data and doing something with it,” she said during a panel discussion at Inman Connect San Francisco. “Don’t create a big pool of data and just leave it there. Constantly update it to make that data better, smarter and more useful…