It's generally been a good time to be long the stock market. The S&P 500 has risen 16% over the past year, and there are naturally several stocks that have performed even better.

Square (NYSE:SQ), Twitter (NYSE:TWTR), and Netflix (NASDAQ:NFLX) have more than doubled since March 21, 2017. The stocks have delivered life-altering wealth over the past 12 months. Let's explore how they have rocked the market and what the future may hold for investors. 

Two men in T-shirts making a Square transaction at a bicycle shop.

Image source: Square.

1. Square -- Up 246%

Two hot trends over the past year are cryptocurrency and cashless transactions, and Square is riding both. Square has enabled merchants of all sizes with the ability to complete credit card transactions, and it's at the forefront among leading public companies in embracing cyrpto as an early adopter of bitcoin marketplaces.

This is more than just a trendy crypto play. Revenue growth has accelerated for four consecutive quarters, and some Wall Street pros see the party just getting started. Dan Dolev at Nomura Instinet put out a bullish note last week, playing up Square's prospects in virtual terminal, e-commerce, and capital services. He has a $64 price target on the stock, suggesting that there's more upside even after the meteoric over the past year. 

2. Twitter -- Up 117%

These are interesting times for social media. Twitter has emerged as a leveler of information and ground zero for breaking news. It also doesn't hurt that President Donald Trump can't stay away from the platform.

Investors were concerned a year ago that user growth was stalling, but we've seen daily active users start to pick up the pace as 2017 played out. Earnings have been strong, blowing analyst profit targets away in each of the past three quarters. 

Monetizing its traffic has been a stumbling block. Revenue actually declined through the first three quarters of 2017, before a modest uptick last time out. Recent headlines about data security and third-party audience manipulation are frightening, and Twitter's chief information security officer confirmed reports that he was leaving the company on Wednesday night. The giants of social media have their work to do when it comes to restoring user trust, but no one else seems close to dethroning Twitter as the microblogging platform of choice. 

3. Netflix -- Up 122%

The rich keep getting richer in video streaming. Netflix continues to widen its lead over lesser premium services, closing out its latest quarter with a record 8.3 million more worldwide subscribers than it had just three months earlier.

Netflix's headiest growth is coming from its widening international coverage, but even its seemingly mature stateside market it still finding a way to penetrate deeper with every passing quarter. Valuation is an issue that has come up with the stock hitting new all-time highs this month, but Netflix has never been cheap. Until folks tire of the convenience of streaming Netflix's growing digital vault or some other service finds a way to make inroads into Reed Hastings' dominance, it's hard to bet against Netflix.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.