The sweet smell of success could be detected in the South Bay on Thursday as the Cannabis Business Summit and Expo brought dozens of companies and thousands of attendees to the San Jose McEnery Convention Center.

Nearly 6,000 people are expected to come through the three-day event that started Wednesday and features everything from the latest in weed-growing technologies to companies working on helping marijuana-related startups get venture financing.

Several attendees said the marijuana scene Thursday reminds them of the early days of the Bay Area tech boom.

"It's not the tie-dye days anymore, it's not that whole culture that was here before," said Sean Kali-Rai of the Silicon Valley Cannabis Alliance. "This is big business. This is Silicon Valley merged with cannabis, and this is what you get; you get a massive industry."

There are still barriers cannabis companies face. Because of federal laws outlawing marijuana sales, the companies can't use banks and therefore must pay their employees and taxes with cash.

The event runs through Friday.