Is creating a database from scraped data and use it to monitize my app is okay?

Which one is best for scratching the web ReactPhp, js, Python?

Which one could be better to do scraping the web. There are more than 10 million pages and must be fast. It can take 1 month with php curl. I'm waiting for your help

How does Google fetch news posts from different websites?

How do I redirect to another page after I've opened the response page after form submit action which needed username and password for login?

eg. http://a.com has a form. I have used mechanize to submit the form and as a response, I get the home page after which I want to direct my virtual browser to http://a.com/details.html so as to scrape some of my data.

Which language would you recommend for web scraping?

Have you ever tried scraping a website? Which language did you use? I am planning to use Node.js (JavaScript), Java or Python. What do you think?