Forum posting is also a way to create backlinks but you should use it in the right way. If you use forum sites for your website promotion and create unnecessary links then this will go into spam, and your account will be terminated by the moderators.
How much work do you really do? If you have seen results you keep working it. Link building is the strongest way of achieving traffic but must be reciprocated. No point sending off all your clicks for no return. I assume your writing the content.
Spamming forums with promotional posts will get you banned and the links you get from it will be worthless even if the moderators don't remove your posts. As with everything else, there is a wrong and right way to go about getting links from forums.
In some niches, there is enough outreach and collections of resources on the topic. In others, blog grids and link levels work fine. Third — with Pinterest, you can get the kind of traffic that you can't get in Google, even if you reach the traffic ceiling in your topic. Webmasters also use a fairly large arsenal of tools for various tasks. Each of them has a set of tools and services, it is impossible to do without them, otherwise you will not be able to build the right links for customers and your sites
Forums link building is good for improve your ranking. But there are some factors you have to keep in mind before posting
1. Post in revelevant forums
2. Do not build aggressive forum profiles
3. Do not use accesive ancher text while posting threads.