Google tends to ignore some links as they do not provide a true representation. A true link signal is when the publisher links to a webpage that should be informative and useful. A few tactics that do not result in popular link building tactics are:
1. Historical Data Link Trap
Here, you must avoid adding links to previously published blogs or articles to affect Google as it may not work.
2. Free Products Link Building
It can be illegal while doing, so you can violate some terms and conditions that are against publishing reviews.
3. EDU Discount Link Building
A discount link-building technique can lead to a penalty stated by Google.
4. Viral Link Campaigns
Sometimes viral link campaigns tend to result in irrelevant inbound links, which will not help to rank the site for vital searches.
5. Content Marketing Links
While uploading content on a third-party site and making a payment for it can violate FTC guidelines.
6. Scholarship links
The issue with scholarship links is they contain irrelevant content, which is why you should avoid them.
7. Sponsor links
The best links are those related to your website, and if you get sponsor links, it cannot help in ranking your site higher.
8. Badges for Links Trick
It is an outdated and oldest link-building track and creates a fake aware strategy displaying an image badge.
9. Charity Link Building
It is a sponsorship link-building process and includes irrelevant links that you must avoid.
10. Content Syndication
It is where content is created and posted in exchange for a link. It is a variation of guest posting to be avoided.
11. Buying websites
Redirecting the domain is no longer going to help you because Google does not pass the link signals.
12. Blog comments
It is considered the worst link-building tactic that search engines have created, and it is known as no-follow.
13. Widget Links
It is one of the oldest scaled link buildings and does not as of now. Google has even published a blog post to warn people against the technique.
14. Contests for Links
It is a situation where other sites are getting linked to your website, but they do not have anything to do with your topic.
15. Profile Link Building
Here people sign up to drop a link, but they are of zero relevance and context that you must avoid. If anyone is recommending you, make sure to avoid it.
16. Press Release Link Building
The websites syndicating press releases tend to have lower quality and Google tends to ignore them.
17. WordPress Theme Link Building
This technique stopped working fifteen years ago, and you should know about it.
18. Forum Spamming
Forum spamming is a platform containing unrelated and related advertisements, abusive language or trolling, links to malicious activities, etc. If you do not want your brand to publicize in the wrong light, avoid forum spamming.
If you keep the above things in mind, you can avoid being caught by Google. As a result, you can know how search engines use links.