Basically if you're in college and reading this on HN don't listen to HN comments that discount equity or value it at zero.
Know that it's hard to value, but that isn't the same as zero. It could be worth millions, it could be worth nothing, it could be worth somewhere in between.
There are lots of angel investors in the bay area because of exits that netted them 2-5M or higher ($10-20M) as regular employees. This feedback loop is part of the reason the bay area generates so many companies.
It's a bet like anything else, try and judge what kind of people the founders are and how solid the business is. Learn about ISOs and what questions to ask/how the basics work (things like the linked article here). It's an investment - owning equity in a good company is the quickest way to get real wealth if you don't already have a lot of money.
Ignore a lot of the people that make over-confident statements about it being worthless, consider the risk, value the company and founders, decide for yourself.
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Today Stripe seems like a good choice to get a good equity return as an employee on IPO, Roblox and Robinhood are others. It's not obvious how things will turn out, but it's not impossible to make a good guess.