A website I know of which provides raw data is called SimilarWeb. The website is used for market intelligence. Supposedly, the information is derived from a complex blend of non-intrusive digital signals that include crawling, first-party direct measurement, external partners, and anonymous behavioural data from their contributory network.
SimilarWeb provide this information to their paying customers as they believe it can help people understand the stock market better. I do not know the reliability of this resource or the efficiency. However, I would imagine if the information they provide is actually helpful to stock market buyers, then this would be extremely important for people related to that field.