India, Nov. 3 -- Adam Robinson, an Austin-based tech entrepreneur known for building multi-million-dollar software companies without venture capital, was among nine people killed when a private Learjet 60 crashed in Palm Beach County, Florida, on Sunday.

Adam Robinson, 44, was the founder and CEO of Retention.com and RB2B, two successful bootstrapped companies that help businesses identify website visitors and access B2B contact information.

Before becoming an entrepreneur, he worked on Wall Street at Lehman Brothers and Barclays Capital. He later moved into business, launching several ventures, including one he eventually sold.

Robinson was a strong supporter of building businesses without outside investment. He regularly shared his e...