Google couldn't win a lawsuit against a company that sold pieces of cardboard that fit over a monitor to block ads. Same thing for Rapportive, which doesn't rem

Google couldn't win a lawsuit against a company that sold pieces of cardboard that fit over a monitor to block ads. Same thing for Rapportive, which doesn't remove any ads itself, they simply offer users a tool that happens to do that as part of its functionality. Also, Google is simply not a very litigious company. They would be much more likely to engage in a technical game of cat and mouse (e.g. make it hard to remove the ads) than sue someone. I wouldn't be worried about creating something like Rapportive. At worst you're like a company that sells lock picks. The onus is on your customers to stay within the bounds of the law (or ToS).