Spam is unsolicited, irrelevant advertising blindly sent to as many email addresses as possible. There are a few reasons why spam is considered to be dangerous for recipients:
Because of this, Internet Service Providers (ISPs) and Email Service Providers (ESPs) implement spam filters to protect users from spam emails. Unfortunately, many legitimate emails may wind up in the spam folder as well, because of certain things which can be easily overlooked. It is essential to take any and all steps to help your emails reach your subscribers' inbox instead of their spam folder.
Major ESPs like Yahoo, Gmail, and AOL have spam filters built into their service.These filters look for certain phrases in the subject line to determine which emails are spam and which are genuine. Some of these phrases include "weight loss", "FREE", and "earn from home".
These filters also make determinations about an email based on the user's engagement. If the user opens, clicks or adds a sender to the contact list then it is less likely to be categorized as spam. On the other hand, if the recipient never opens your email or deletes it without reading the content, then you are more likely to be classified as spam by these filters.
ISPs use similar mechanisms as ESP spam filters to judge the sender's domain. The only difference is that ISPs are more powerful. When they notice a domain is constantly sending email spam, they can simply blacklist your domain. When this happens, any emails sent from that domain will be blocked. If this happens, you must contact any ISPs who have blocked you in order to be whitelisted again.
Emails to people who haven't opted-in - Never try to email people who haven't opted-in to your emails. Sending messages to uninterested people will degrade your domain's reputation and could lead to blocking or blacklisting. Domain reputation is something that many customers share, so the impact on its reputation means many will suffer. We strongly recommend sending messages to double opt-in contacts only.
Using a purchased mailing list - It is best to avoid this practice for the good of your domain and business. The companies that sell contact lists generally don't spend much effort to make sure their contacts are interested in their customers' products. There may even be spam traps in these mailing lists. To learn more about spam traps click here.
Unauthenticated domain- It is best to authenticate your domain with SPF and DKIM in order to comply with DMARC standards and avoid any vulnerabilities.
Scofflaw marketers - Make sure all of your marketers adhere to all spam laws, including CAN-SPAM, GDPR, CASL, and more. If these laws are not followed, your domain is at risk of a degraded reputation, or even legal retribution.
Unsegmented, unkept mailing lists - When your mailing list is old and unsegmented; there can be a lot of chaos and irrelevant addresses. Unclean lists lead to spam traps, bounces, and more complaints against your domain. Make sure you constantly check your list and keep it updated. Segmentation can help make things easier for marketers who want to contact specific groups.
Too much/too little contact - If you either flood your subscriber's' inbox or abandon your subscribers, you'll wind up with more complaints and unsubscribes. Ask for their preferences when they sign up for your mailing list, and you can avoid too much or too little contact.