Binary option are evil and scam brokers
However, these sites are the exception rather than the rule and there is no reason to believe that the exclusion of these sites from the study will cause a systematic bias in the sample. The domain name generated in this way may not be a valid URL, that is, such a website may not exist. Therefore each domain name generated needed to be verified.
If the attempted connection to a randomly generated URL was unsuccessful after three tries, then the URL was discarded and another URL was generated and the connection tested again. The process continued until a sufficiently large number of valid sites was found for a further filtering process (described below).