Data scraping is a technique where a computer program extracts data from human-readable output coming from another program.
Data scraping is most often done either to interface to a legacy system, which has no other mechanism which is compatible with current hardware, or to interface to a third-party system which does not provide a more convenient API. In the second case, the operator of the third-party system will often see screen scraping as unwanted, due to reasons such as increased system load, the loss of advertisement revenue, or the loss of control of the information content. (Wikipedia)
Data scraping or web scraping, is the process of getting information from a website into a spreadsheet or local file saved on a computer either local or in the Cloud. It’s one of the most efficient ways to get data from the web. Web scraping is legal if you scrape data publicly available on the internet. Some kinds of data are protected by international regulations. Olery scans millions of pages daily for new reviews, collects and stores them through various technologies in near real-time.