That’s true, getting a thousand of backlinks overnight, which can be done only in a spammy way, is an absolute no-no and frequently results in sites being sent to Google sandbox. Still, backlinks are the key to off-page optimization, PR and SERPs visibility, but, to put it briefly, the quality of these links makes optimization effective, not their quantity.

For instance, good old directory submission and article submission still work, but only if you submit unique articles to respected directories in your niche. Guest blogging is one of the best off-page techniques, and it again deals with the content, which is engaging and valuable for readers. Overall, it seems that content marketing is becoming an adjacent discipline to SEO and needs to be incorporated in an SEO strategy at some point.

I would also say that social media presence gained a lot of importance recently and all kinds of social signals are worth focusing at, since they are paying off in terms of both SEO and traffic inflow.

After panda and penguin, and the recent days, SEO is going natural and also spamming software cant get the search result even through your business Google sandbox.

So why you will get spammy program as you want to make $ online...?

You can PM me for safe search engine optimization #1 ranking.

Think about it this way. There's no set magical number of spammy backlinks that will send your website to a google sandbox. The better your 'reputation' with Google, the more spammy backlinks are needed to bring it down. Also, relatively new websites are not targeted by competitors as they are not seen as a threat. That being said, as soon as a new website starts taking market share from the competitors, it already has some reputation with Google, and taking it down becomes much harder.

... And there's always the disavow tool.

I'm not sure "negative SEO" is a reality - in the sense that you can undermine your competitor by spamming with his links. There's a lot of talk that it IS - but NOT in my experience.

I observe that low-quality links are simply rewarded MUCH less, so if a competitor already has good authority and lots of healthy links, you can't hurt him. And vice versa.

Of course negative SEO is possible.

Totally agree with what Associate9 said above though. Attempts at negative SEO are just as likely to backfire as they are to have an effect. And if they have an effect, then disavow.

If negative SEO wasn't possible, Google wouldn't have needed to release the disavow tool.