AP Photo/Richard VogelPeople riding Lime and Bird scooters in Santa Monica, California. Micro-mobility was one of this year's top startup trends identified by LinkedIn.Jessi Hempel, a senior editor at large at LinkedIn, looked at data tracking the actions of users on the popular social-media platform.She helped build a list of the top 50 startups of 2019 based on growth, user engagement, job interest, and the quality of jobs employees left to join a startup.Hempel talked to Business Insider about the five trends, which were meant to answer the question What about the nature of work is changing?Click here for more BI Prime stories.Three years ago, perhaps no one thought a cannabis company would be one of the fastest-growing startups in the US.Yet this week, the cannabis-pen company Dosist claimed the second spot on LinkedIn's list of the top 50 startups in the US - and more impressively, it's the first cannabis-centered startup to make the list.Business Insider reviewed the ranking, then spoke with an editor who coauthored it to see what she considered the most interesting trends in the startup world.For example, Silicon Valley is known for its startup culture, but Jessi Hempel, a senior editor at large at LinkedIn, pointed out that six out of 50 startups on this year's list were actually based in Los Angeles.LA is really coming of age as a startup hub, Hempel told Business Insider, pointing to a slightly lower cost of living than that found in San Francisco and New York City. Perhaps even more crucially, she said, startups are finding it easy to find capital there.The emerging trends from LinkedIn's study are based on the decisions of more than 645 million users. Startups qualify for consideration for the list if they are seven years old or younger, are independent and privately held, and have 50 or more employees. They're more likely to make the list if they're increasing their employee base by at least 15% year over year and have high levels of external engagement. Interest in jobs as well as the quality of jobs employees left to join a startup were also factors.When LinkedIn's editorial employees, including Hempel, looked at the resulting list of startups, they asked: What about the nature of work is changing?The following five trends are answers to that question, along with breakout startups leading those trends and where they fell on the ranking.