In the rising world of social media, 2015 was an eventful year full of historic moments.

Some, it's true, were pretty cringe-worthy--like when Alec Baldwin tweeted a complaint that minimum-wage protestors were disrupting his afternoon commute. Others, such as the hugely influential #BlackLivesMatter hashtag, proved that a small gesture can ultimately reach millions, and start an important national conversation.

Here are some of the top social media moments of 2015.

1. Lena Dunham hands off Twitter, but keeps Instagram.

On September 28, the actress, producer, and entrepreneur announced she would be handing off her Twitter account to a third party--due to bullying.

"I really appreciate that anybody follows me at all, and so I didn't want to cut off my relationship to it completely, but it really, truly wasn't a safe space for me," she said in an interview with Re/Code.

Instagram, she noted, is a more positive atmosphere: "The presence of images and no character limits creates a much less toxic environment," she said on stage at Vanity Fair's New Establishment summit in October.

2. The world responds to Ahmed Mohamed's science project.

In September, 14-year-old Ahmed Mohamed was arrested and questioned  for bringing an electronic clock in a pencil box to his high school, which school officials said resembled a bomb. 

Following the incident, he received an outpouring of support from social media--particularly on Twitter--where users alleged racial profiling and Islamaphobia on the part of officials involved. 

Following the incident, Mohamed appeared as a guest of honor at Google's annual science fair. He also received a special invitation to White House from President Obama.

3. #BlackLivesMatter.

Initially created in 2012, following the death of Trayvon Martin, the #BlackLivesMatter hashtag has since continued to raise awareness for police brutality, violence toward black Americans, and racism in the criminal justice system.

Led by Alicia Garza, Patrisse Cullors, and Opal Tometi, the organization was created to turn the conversation into social action. Following the additional deaths of Tamir Rice, Eric Harris, Walter Scott, Jonathan Ferrell, Sandra Bland, Samuel DuBose, and Freddie Gray, #BlackLivesMatter began to formally challenge politicians to express their views on the matter.

In 2015 alone, the hashtag was used more than nine million times.

4. #JeSuisCharlie.

In January 2015, Islamist terrorists attacked the headquarters of the satirical French newspaper Charlie Hebdo, murdering 12 people. In the days following the attacks, the #JeSuisCharlie hashtag (French for "I am Charlie") went viral as an expression of support for those affected. 

At its height, #JeSuisCharlie was tweeted 6,500 times each minute, making it one of the most popular hashtags in Twitter history.

5. President Obama joins Twitter and Facebook.

In May, President Obama started his own official (@POTUS) Twitter account. He then set a Guinness World Record for reaching more than one million followers in five hours.

"Hello, Twitter! It's Barack. Really! Six years in, they're finally giving me my own account," read his first tweet.

In November, the president created a Facebook account, in hopes of having "real conversations" with the public. His first post addressed climate change. 

"I want to make sure that the American people are able to enjoy the incredible national parks, incredible beauty, the mountains, the oceans, that have been one of the greatest gifts we've ever received," he said in a video post.

6. #LoveWins.

Following the Supreme Court ruling in June that gay marriage must be recognized across all 50 states nationwide, celebrants spread the word on social media by using the #LoveWins hashtag. Within the first six hours following the decision, it was tweeted more than six million times.

Facebook, similarly, gave users the option of overlaying their profile picture with a rainbow flag. As many as 26 million edited their Facebook photos accordingly, including Mark Zuckerberg.

7. Edward Snowden joins Twitter.

Not one to miss out on the fun, NSA (National Security Administration) whistleblower Edward Snowden joined Twitter in September using the handle name "@Snowden." He now tweets from his exile in Russia. 

He first tweet:

Within 30 minutes of creating the account, Snowden had more than 70,000 followers. Today, he has 1.7 million, but he follows only one account: the NSA's.

8. Slack proves that Twitter is a customer-support tool.

Teams across the nation began to panic when Slack, the fast-growing workplace messenger tool, went down one Monday morning in November. Thankfully, the company's adept social media team was able to assuage customer fears, and keep them in the loop regarding service updates. The system was fully restored three hours later.

9. Alec Baldwin shows how not to do social media (again).

In April, the actor took to Twitter to express his outrage over protestors blocking the streets of New York City. (They were rallying for a higher minimum wage of $15.00 per hour, otherwise known as the Fight for 15 campaign.)

"Protestors have blocked off a huge quadrant of midtown traffic in support of a higher minimum wage. I support their goal, not their method," Baldwin tweeted through the affiliated @ABFoundation account.

He stoked the ire of New York Times correspondent Rachel L. Swarns, who wrote in an article: "The next time you're stuck in traffic because of a rally for a living wage, please don't pick up your smartphone to post your complaint on Twitter."

10. Tinder goes berserk.

In response to an article published in Vanity Fair in August (which took a critical look at modern urban romance via dating apps--Tinder included), the dating startup issued a 30-part defense on Twitter. One tweet, for example, read: "If you want to try to tear us down with one-sided journalism, well, that's your prerogative."

The response was read as utterly desperate and provoked several news articles re-displaying the aforementioned tweets.

"You cannot let your emotions run wild on Twitter," said Steve Cody, a public relations executive (and co-founder of Peppercomm), in an interview with Inc.