What is the difference between Selenium IDE, Server, RC, 2.0, and WebDriver?

Question

Selenium seems to have a lot of different components and the website does not explain them very well and I'm still a bit confused which is which. What's the difference or purpose between:

Selenium IDE Selenium Server Selenium Remote Control WebDriver Selenium 2

My understanding is as follows:

Selenium IDE is a GUI plugin used for rapid prototyping of test cases in Selenese/HTML.

Selenium Server is a standalone java program that allows you to run HTML test suites in a range of different browsers, plus extra options like reporting.

Selenium Remote Control is the old name for Selenium Server, which only supports version 1 of the Selenium API.

WebDriver is the actual core API which has bindings in a range of languages and allows you to write standalone tests.

Selenium 2 is the latest version of the Selenium project and includes the IDE, Server, and WebDriver.

Answer 1

Selenium IDE 

1. It's an add-on that is only supported by the Firefox browser.

2.  Selenium IDE  brings one of the most valuable record and playback feature.

3. It is independent of the Selenium server to run the test script.

4. You may not use it to move mouse cursors.

5. You can readily use its record & playback feature.

RC

1. It’s an API that supports Firefox, IE, Chrome, Safari, and much more.

2. It uses the Selenium server before processing the test script.

3. It’s a standalone Java (jar) application that runs Html test suites in the browser.

4. Its APIs are not fully object-oriented.

5.iPhone/Android applications are not supported.

WebDriver

1. It works with every browser like Firefox, IE, Chrome, Opera, and others.

2. You can’t use it for recording and playback.

3. It is a full-fledged API, and languages like Java, Python, and CSharp implement Webdriver APIs.

4. It allows for managing the movement of mouse cursors.

5. Selenium Server isn’t needed anymore to run the test script.

Selenium  Server 

It is a standalone java program that allows you to run test cases written in a variety of programming languages with a variety of web browsers, and which can additionally run HTML test suites in a range of different browsers as it supports multi-browser compatibility, also choices like reporting. (My point is that the --HTML suite option of selenium-server.jar is not its primary function, and will soon be split out into a separate program.)

Selenium 2.0

(Selenium IDE + Selenium RC + Selenium WebDriver + Selenium Grid)

Selenium 1.0 + WebDriver = Selenium 2.0

Selenium 1 and WebDriver merged to produce a better product—Selenium 2, or Selenium WebDriver, which was released in 2011. Selenium 2 has the clean and object-oriented APIs from Web Driver and interacts with browsers in the best way possible for that browser. Selenium 2 does not use a JavaScript sandbox, and it supports a wide range of browsers and multiple language bindings. Selenium 2 provides drivers for:

1. Mozilla Firefox

2. Google Chrome

3. Microsoft Internet Explorer

4. Opera

5. Apple iPhone

6. Android browsers

With Selenium 2, you can write tests in Java, C#, Ruby, and Python.

Selenium 2 also offers a headless driver based on HtmlUnit, which is a Java framework for testing web applications. HtmlUnit is really fast, but it is not realistic as a driver associated with a real browser.