If the subject line of the email is irrelevant to customers, they will ignore it multiple times. But, if it keeps repeating, they are intercepted and unsubscribed from your emails. So, send relevant emails for the benefit of the customer. Don't send emails that often only focus on sales, offers and discounts.
The whole algorithm can be expressed in psuedocode like so:，更多细节参见搜狗输入法2026
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a Bureau of Standards design competition and the twists and turns of industry，详情可参考同城约会
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