Biggest Tech Moments That Has Us Talking in 2015

From the Apple Watch to hacks galore, a look back on the year in tech.

— -- From new products to play with to hacks galore, 2015 was a wild year in technology.

Here's a look at some of the products, people and some of the out-of-this-world moments that helped define the year.

Apple's first wearable device hit stores in April -- and in the months since, it's been astounding to see what people can control from the small screen on their wrists.

Much of the interaction on the watch is driven by notifications. The Apple Watch to keep you on track for your appointments, advise you when you may need an umbrella or show you a text message from a friend. It can even control connected home devices through Apple's HomeKit platform.

It's a new era for Google as the search engine giant becomes a part of new holding company Alphabet Inc.

The decision to slim down Google and make it a subsidiary of the newly created Alphabet was announced in August and is intended to allow each company to focus on what it does best. Google has always been a search engine and advertising business at its core but over the years it's grown into a company with diverse interests, ranging from self-driving cars to home automation systems.

The idea of Alphabet is to spin off some of those businesses from Google, letting each one focus on what they do best.

Microsoft's free Windows 10 upgrade rolled out this summer with some key changes.

There's a sharper new browser that puts Internet Explorer to shame, Cortana integration and an emphasis on a more productive experience in Windows. Windows 10 is so radically different that Microsoft even skipped over naming it Windows 9.

Home Brew Servers

When the issue of Clinton's email habits as secretary of state first came to light in March, she explained she chose to use a personal account out of convenience and added that all of her business-related emails were going to employees, making them a part of the official record.

"Looking back, it would have been better if I'd simply used a second email account and carried a second phone," she said in March. "But at the time, this didn't seem like an issue."

Ashley Madison, the website for married people seeking affairs, suffered an unprecedented hack, putting as many as 37 million members and private information from the website's company, Avid Life Media, at risk.

Data dumped online by the hackers included purported personal information from people who signed up for the service -- putting millions of alleged would-be cheaters at risk of be discovered.

Noel Biderman, the CEO of Avid Life Media, the parent company of Ashley Madison, announced after the hack he would step down.

The Zuckerbergs are planning to give away what amounts to about $45 billion at today's value, but the gift will be spread out through their lifetime.

Facebook Cracked 1 Billion Daily Active Users

Every day, one billion users -- that's 1 in 7 people on the planet -- check Facebook. Hitting the billion user milestone just 11 years after Facebook was founded. CEO Mark Zuckerberg said "it’s just the beginning of connecting the whole world."

Hoverboard Fire Concerns

The hottest toy of the holiday -- the hoverboard -- has come under scrutiny after some of the devices have reportedly caught fire. The self-balancing scooters have been banned from many major airlines over concerns the device's lithium ion batteries may be a fire hazard.

The Consumer Product Safety Commission said earlier this week it was investigating 12 hoverboard-related fire incidents in ten states.

Jack Dorsey Returns to Twitter

Jack is back!

Jack Dorsey, 39, the former CEO of Twitter and one of the founders of the site, took over once again as chief executive in October after serving as interim CEO. Dorsey's appointment to his old position came three months after Dick Costolo stepped down from the top job. Dorsey has also continued to serve as CEO of mobile payments company Square, which began trading publicly last month.

New Horizons Reaches Pluto

Blue skies, water ice and that conspicuous heart-shaped region were just a few of the many discoveries the New Horizons space probe made as it whizzed past dwarf planet Pluto. The nearly ten-year trip to reach Pluto yielded a trove of data NASA scientists are still downloading and analyzing on Earth.

The piano-sized probe is speeding through the Kuiper Belt, an area at the edge of our solar system. After the intensive data transmission process, NASA is considering another flyby of a Kuiper belt object known as 2014 MU69 that orbits nearly a billion miles beyond Pluto.