(The following comes from Patrick Knight, Director of Client Deliverability for mobileStorm.)
In the world of email, bought lists are pretty common. Buying a list is not against the law per se(CAN-SPAM never specifically states it); however it’s not such a safe bet since it’s not necessarily clear how these lists are compiled. In many cases they contain addresses that were collected by third-parties who use pre-checkboxes, `and or contain harvested, spam traps (old addresses used to monitor and identify spam activity) and invalid addresses (addresses that are no longer active and bounce).
Contrary to what many marketers think, purchasing lists is not very cost effective, when you consider the facts. Anywhere from 80-90% of these lists have data that is useless. Not to mention the costs marketers incur by having to resolve issues as a result of using these lists.
There is never a time when you should send messaging to people who didn’t opt in. The question to ask your self is …Did these people request to be on my list? Do they expect to receive emails from you, have you sent emails to these people before. The main point here is consent. These people did not give you permission to send them messages.
Those marketers who do buy lists run serious risks. Beside the fact these people never sign up to receive your messages, even if you were to perform a permission pass campaign you run the risk of hitting spam traps, and in the end, it’s just not worth the risk.
A sender’s reputation is based on measuring many variables including, spam trap hits, number of complaints, and invalid addresses. As mentioned, many of these lists contain addresses that affect these variables negatively which can hinder if not ruin a good senders reputation.
Ultimately, good senders can end up being listed by major blacklists. IP addresses used to send messages in some cases can be permanently blocked. Furthermore, subscribers who have given permission to receive messages will most likely not receive it because of blocks place on your IP. It may also take a significant amount of time and resources to repair your reputation. If utilizing an ESP this can also cause collateral damage to your provider.