Here's how it works: When a company signs up with Conversica, they get to pick the name, gender and title of their new assistant. As leads come in, the AI assistant gets in touch with them through email or text message. If a lead is interested, the AI assistant routes the communication to a real-life member of the sales team to close the deal.

One advantage over humans is the AI isn't put off by unanswered emails — it doesn't mind being ignored or forget to follow up, so it can be programmed to be more persistent, emailing weeks after the initial contact.

"She has a name. She has a title, an email address and a phone number," said Alex Terry, CEO of Conversica. "She reads and writes emails and SMS text messages back and forth with leads."

Conversica has about 1,000 companies that use the platform, Terry said, and about 250 million messages have been sent so far, giving the company a pretty robust sample size to see what makes an AI assistant successful. A lot of that has to do with how they're set up in the first place. For one thing, the data suggest that the gender of the assistant is important and customers often like to think they're communicating with someone young.

"What we tend to find is female names outperform male names in general," Terry said. "And most commonly names that were popular 24 or 25 years ago tend to do pretty well."

The most common names for companies to name their AI assistants are popular female names from the 80s and 90s like Ashley and Stephanie: They're both in the top five in terms of the most leads worked.