dstiles - 7:40 pm on Aug 24, 2013 (gmt 0)
If you cannot detect source IPs and make decisions on blocking them then your web site is toast. It WILL be scraped by everyone and their goat.
Primary defence against this is to detect source (and/or proxy) IP and block all coming from server farms, including all of Amazon, most of google, and so on. There are major lists of IPs to block in this forum but the list is by no means definitive.
Secondary defence includes bad user-agents, bad headers and more. Again, check previous postings in this forum.