The most important thing when it comes to website data collection, I'm talking about product research in particular - time that goes into this process could be much better if you'll use such tool as we are doing now! We've solved an issue of high volume customer requests for products info (price lists), which previously had so many manual checks done by our team members each month; but with new solution they went down almost half-fold compared to before using these tools. The ease of use, flexibility to customize your own rules, ability to access all sorts of data from different sources with one tool. It's not free but it has some good features that make up for this. I can't think of anything specific at the moment. If you are looking into web scrapers, look no further than Web Robots! We have been able to pull in information from multiple sites without having to manually check each site individually.