computer science

Like button

Like button is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Like button rather than just read about it. In short: A like button, like option, or recommend button is a feature in communication software such as social networking services, Internet forums, news websites and blogs where the user can express that they like or support certain content. Internet services that feature like buttons usually display the number of users who liked the content, and may show a full or partial list of them.

Key takeaways

Like button belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Like button to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Like button from memory before moving on to harder problems.

Reference excerpt

A like button, like option, or recommend button is a feature in communication software such as social networking services, Internet forums, news websites and blogs where the user can express that they like or support certain content. Internet services that feature like buttons usually display the number of users who liked the content, and may show a full or partial list of them. This is a quantitative alternative to other methods of expressing reaction to content, like writing a reply text. It is the most used feature on social media. Some websites also include a dislike button, so the user can either vote in favor, against or neutrally. Other websites include more complex web content voting systems; for example, five stars or reaction buttons to show a wider range of emotion to the content.

Implementations

Vimeo Video sharing site Vimeo added a "like" button in November 2005. Developer Andrew Pile describes it as an iteration of the "digg" button from the site Digg.com, saying "We liked the Digg concept, but we didn't want to call it 'Diggs,' so we came up with 'Likes'".

FriendFeed The like button on FriendFeed was announced as a feature on October 30, 2007, and was popularized within that community. Later the feature was integrated into Facebook before FriendFeed was acquired by Facebook on August 10, 2009.

Facebook

The Facebook like button is designed as a hand giving "thumbs up". During development, engineers, including Andrew Bosworth, Leah Pearlman and Justin Rosenstein, initially considered designs based on a star, a plus/minus button, or a heart, and the feature was internally referred to as the "awesome button" before being renamed at Mark Zuckerberg's direction. It was introduced on 9 February 2009. In February 2016, Facebook introduced reactions - a new way to express people's emotions to Facebook posts. These reactions include "Love", "Haha", "Wow", "Sad", and "Angry". The "like" button influences Facebook's algorithm by affecting how content is ranked and distributed in users' feeds. On the other hand, a study highlights the disadvantage of the "like" reaction in algorithmic content ranking on Facebook. The "like" button can increase the engagement, but can decrease the organic reach as a "brake effect of viral reach".

YouTube

In early 2010, as part of a broader redesign of the service, YouTube switched from a star-based rating system to Like/Dislike buttons. Under the previous system, users could rate videos on a scale from 1 to 5 stars; YouTube staff argued that this change reflected common usage of the system, as 2-, 3-, and 4-star ratings were not used as often. In 2012, YouTube briefly experimented with replacing the Like and Dislike buttons with a Google+ +1 button. In 2019, after the backlash from YouTube Rewind 2018, YouTube began considering options to combat "dislike mobs," including an option to completely remove the dislike button. The video is the most disliked video on YouTube, passing the music video for Justin Bieber's "Baby". On November 12, 2021, YouTube announced it will make dislike counts private, with only the content creator being able to view the number of dislikes on the back end, in what the company says is an effort to combat targeted dislike and harassment campaigns and encourage smaller content creators. On October 17, 2023, with an update on the website, views and likes will be updated periodically during the first 24 hours of a new video. Additionally, the Like button will "glow" when a creator asks their viewers to press the Like button. In addition to videos, each of their user comments also have its own set of Like and Dislike buttons since August 2007. The feature was originally implemented in a similar fashion to Reddit's system of Upvotes and Downvotes until a greater redesign of the comment system in September 2013 (initially oriented on Google+), since which – while comments continue to show their Likes count – Dislikes won't be made public and thus have no visible effect on a comment's rating. Since June 2026, YouTube has removed the dislike button in the Shorts section, in addition to changing the thumbs-up icon to a heart.

Google+

Google+ had a like button called the +1 (Internet slang for "I like that" or "I agree"), which was introduced in June 2011. In August 2011, the +1 button also became a share icon.

On Reddit (a system of message boards), users can upvote and downvote posts (and comments on posts). The votes contribute to posters' and commenters' "karma" (Reddit's name for a user's overall rating).

X / Twitter

Alongside reposts (commonly known as retweets), X (formerly Twitter) users can like posts made on the service, indicated by a heart. Until November 2015, the equivalent of "liking a tweet" was "favoriting a tweet" and favorites were symbolized by a gold star (). However, that was changed to alleviate user confusion and put the function more in line with other social networks, the favorite function was renamed to like. Previously users were able users to see which tweets others have liked under a likes tab in a user's profile. Though in June 2024 this feature was removed across the site thus making likes private for all users. In July 2024 it was reported that a "dislike" button featuring a broken heart icon was being tested as an addition to the site.

VK VK like buttons for posts, comments, media and external sites operate in a different way from Facebook. Liked content doesn't get automatically pushed to the user's wall, but is saved in the (private) Favorites section instead.

Instagram The Instagram like button is indicated by a heart symbol. In addition to tapping the heart symbol on a post, users can double tap an image to "like" it. In May 2019, Instagram began tests wherein the number of likes on a user's post is hidden from other users.

TikTok The TikTok like button is indicated by a heart symbol, and users can use the like button by double tapping on a post they like, similar to YouTube Shorts and Instagram. Liked content can be accessed via the "Liked" tab on a user's profile. Additionally in 2022, TikTok implemented a Dislike button for their user comments with the intent of giving their users power to identify comments that are considered "irrelevant or inappropriate". Just like on YouTube ever since the late 2013 overhaul of their comment system, these dislikes are not visible to others.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Like button

Start with the simplest possible case. Write down what Like button claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Like button before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Like button ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Like button

In research: Like button appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Like button in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Like button is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2000s neologisms, Social software, Software features, so understanding it makes those chapters shorter.
In everyday life: Look for Like button outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Like button in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Like button means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Like button out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Like button in simple terms?

Why does Like button matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Like button?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Like button.