You missed a key question here. As a business owner, what on earth do I need to do next?? Do I need to email all my users giving them an opt-out option?!
>>thisis+(OP)
Working on that, there will be a second installment on Monday and - possibly, if I can find the time - a third with a number of case studies.
This whole sequence was sparked through a discussion about the GDPR on HN a few weeks ago and I've been working on it off-and-on hoping to get it done before the law becomes enforceable.