Backlinks affected on the loss of one website

If we are generating backlinks on a single website, we would expect that it will generate more backlinks and traffic to our site. But what happens when a site is already gone and flushed? Our search optimizing ways are on a bad luck when a site was toasted and gone. Like for example, if we post on a SEO forum about 1,000 backlinks, and after 2-3 months it was totally gone. The result is you lose backlinks, and your rankings could get lower, as well as your traffic too. if you are a site owner like the forums itself, which more and more people promoting their backlinks to their signatures, you must always maintain your forum alive and free from spam.