Their plugin replaces the Google Adwords ads with their own content. Google released a competing widget; why not just sue? Wouldn't Google have a case for they are directly interfering with their revenue stream? I am interested in creating my own Gmail plugin but would like to know the legalities behind this first.
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).
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).