There are lot of ways how to do marketing. You cannot say that one is wrong and other is right. But you can say that one is efficient, and the other one is not.
In this article I will focus on common misconceptions in direct marketing - Email and SMS marketing, that waste time and money, but do not actually raise the efficiency.
Targeting by interest is crucial
In ideal world, yes, that would be true. If for example you have database of casino players sending them another other casino offer would covert really well compared to general database.
But in the reality the are lot problems involved. Where would you get a database of casino players? Casinos don't sell them, so the only way is if it's stolen. But in that case you would have to buy it on black market from a person you know is not trustworthy, so how can you know he's not simply lying to you? It's a lot easier to scam someone by pretending to sell good database, compared to actually stealing such database.
Another way to get targeted data is to collect it via surveys. But let's be honest: people don't really pay attention to what they answer. They just want to win the prize. They may answer "yes" to everything, if they believe it will give them better chance at winning, or alternatively "no" so that they will receive as little spam as possible.
So if you take these facts into consideration, there's really no reliable way to even get data targeted by interest. Not to mention how much you will have to overpay for such, only to find out that the results are average.
Leads need to be fresh
I don't know who came up with that thought, but it has absolutely no logical grounds.
Let's think about it. A person has used specific phone or email for 5 years. In the years he has opted for some newsletters and receives offers on constant basis. Now, would it matter if the advertiser got his email 5 years ago or yesterday? Would it have any effect on how this person would react to ad he receives? The obvious answer is no, so why does the lead has to be fresh?
Some say that leads has do be fresh, because that's how you know the email or phone is still in use. Well there are very cheap and easy ways to check validity of an email or phone number, so it doesn't support this claim either.
Sending to often is a bad thing
Sure, if a person receives 1 offer per week, compared to 10 per day, it's more likely that he will react to it more positively and thus convert better. But you are missing one huge crucial fact. You are not the only one who sends ads to him! Most likely one email is in database of hundreds or even thousands of different companies. And all of them send offers to him. Thus even if they send only once a week, he will get several offers per day. There's simply no way around it. The amount of offers one advertiser sends makes no difference when you look at the bigger picture, thus it would be actually smarter to send as often as you can, because it will raise probability of him seeing your offer, instead of someone else's.
If your database is not opted in you will get into trouble
An average person subscribes to a new newsletter once a week. Many of the data collectors resell their databases, so within a year he's on the list of at least few dozens different advertising companies. Now, can you tell me, how does he keep track of all this subscriptions? He doesn't. So how can he or anyone else possibly prove that you got this personal details illegal way? By the fact that you have timestamp (which can be just any random date and time) and his IP address?
Well IP addresses change often, first of all, most of them are not even static, which means every time a person connects to internet his IP changes. But even if it is static, he uses his home IP, work IP (which can be a lot IPs already), WiFi (every network, new IP), etc. So there's already few dozens of IPs he could use to sign up to a newsletter. Have you ever heard of an authority checking your data to see if an IP matches the location this person could have visited? Neither have I. Nobody checks anything. There's no way to verify is a person has opted to your database or not. Thus you can never get convicted for this crime, as they won't be able to prove your guilt.