What is web-scraping basically?  

• Web scraping is the process of gathering data and content from the webpage. It is used for the collection of data from the internet and storing it in a file. 
• Although, it is cheap one needs to code for it, install and use tools for it. Web scraping uses different methods, which include tools of web scraping for data extraction in form of SQL, Excel, and HTML.
• Some of the common software tools of web scraping using different programming languages are:

1. Java programming language:  Jsoup, Jaunt.
2. Python programming language: Beautiful soup and scrappy.
3. For Node.js: Osmosis and Noodle.

The main purpose of web scraping is to fetch the data for a website that has a lot of scraper traps, captchas.

How does web scraping work?

 Python is one of the popular programming languages one uses for web scraping. For data extraction using web scraping with any programming language (python), you need to follow 3 steps: 

1. Get or select the URL link that is to be scrapped.
2. Find the data class that has to be extracted.
3. Write the code for the same.
4. Run the code and extract a considerable amount of data.
5.  Store the data as per requirement in a specific file format.

Applications of Web scraping 

Some of the commonly used applications of web scraping are as follows:

1. Price Comparison
2. Email Address Gathering 
3. E-commerce websites
4. Social media website content scraping
5. Travel website
6. Job listing
7. Research and Development 
8. Finance websites
9. Data mining
10. Data Journalism

Any website can be scraped. It should be done respectfully and considerably. There is a misconception about web scraping that is, it needs additional tools, scraper alone will do everything needful on its own, it is very hard, and lastly, it's not legal. 

Is web scraping legal or illegal?

Although web scraping is cheap and any website can be scraped, one needs to follow rules and maintain respect for web services.

 There is not any specific answer to this question. Some websites explicitly allow web scraping. 

Some websites don't offer a proper way of guidance on another hand they are not allowed. To avoid any judgemental issue, we should follow all terms and conditions of the website and scrap the data wisely. 

Lastly, web crawling and web scraping aren't illegal and Google search engine does not take legal action against scraping.