Social bookmarking is an effective way to build your online presence. When you add social bookmarks to the web it helps search engines understand your site.
See : https://www.infront.com/blog/what-is-social-bookmarking-and-why-does-it-matter-with-seo/
It shows you more details about what is social bookmarking and why it matter with seo , with benefits , best practices and it shows you top 10 popular social bookmarking sites ,
See : https://www.shoutmeloud.com/how-effective-is-social-bookmarking.html
It shows you how effective is social bookmarking for blog with benefits , andtips with more details .
See : https://www.seoblog.com/social-bookmarking-harmful-seo/
It shows you more details about Is social bookmarking positive or harmful for seo with potential benefits and risk and final verdict .
Final verdict from above ,
If you’re using high quality social bookmarking sites, like Reddit or Pinterest, then sure; you can get some good links, some good traffic, and some reliable readers from it. On the other hand, if you’re automating it, paying for it on the cheap, or otherwise using exploitative techniques, you’re going to pay the price. You might not pay it now, you might not pay it for a few months, but you’ll pay it sooner or later.
Hope this Helps !