| you can verify how full it is. there are some verification focused services - like they take a list of emails and check if they are valid email addresses. Some use fine print to say they are only validating whether or not it is of valid email address FORMATTING, and make no claim about whether or not the email will bounce. verifying if the email address actually belongs to the person it claims to is not part of the deal. it's nearly an impossible task, because you have no actual source of truth to verify it against. So data vendor A and B give you different results for the same search - now what? you have to manually research and see whos "right" or "more recent". even if it looks like good data, it might be stale. For example, company size, revenue, C level email addresses, etc all change over time. so if a customer wants cleaner data - you basically charge them to pump the dataset through Mechanical Turks or upwork or something to have people try to verify things manually. Datasets can be large though and this gets expensive, so it tends to be better to just buy the crap data for cheaper and figure it out yourself I have a conspiracy theory that these verification services are behind a lot of the phone spam today. they are just checking if your phone number is valid, they dont actually care if you answer. |