Email marketing

We have a 2005 customer show profile, including the email address, they are buyers in our industry, and have registered to receive our marketing mailing list. In 2019 we tried to email these customers, 8,000 customers, more than 5,500 have left, or the company has closed. To put it another way, there are about 2,500 professionals who have not changed their positions in the past 14 years, or the company is still operating. Great!