Common Mistakes Made in Ecommerce and PPC as David Szetela welcomes ‎Best-Selling Author, Successful Entrepreneur, Authority on Marketing Optimization with ‎Invesp Khalid Saleh. Khalid Saleh is the CEO and co-founder of Invesp, a leading provider of conversion optimization software and services. He’s the co-author of O’Reilly’s Conversion Optimization: The Art and Science of Converting Prospects to Customers. He is launching his technology startup, FigPii, the one-stop platform for everything related to conversion rate optimization.