First of all, let me tell you online presence IS NOT THE SAME AS social media presence.
I cannot certify / discard the authenticity and applicability of a(ny) specific post (the article, not the survey) found on internet, but given the practical experience, I'd say, it really does not matter much if you do not have social media presence.
Yes, it's desirable to have a professional networking account like LinkedIn, and having some personal pet projects on Github - they count as online presence (i.e., - they speak for your skillset, expertise etc.). However, not having one does not carry enough weight to be considered as one of the criteria for disqualification for interviewing.
On the other hand, as mentioned in the original survey post (not the article you've linked, the actual survey)
The post starts with something
"Before posting pictures of your late-night revelry or complaints about your job on social media, think again – 70 percent of employers use social media to screen candidates before hiring, up significantly from 60 percent last year and 11 percent in 2006."
Which comes off more of a warning about the (improper) use of social media can actually harm your career, as recruiters and employees may get negatively impacted by not-so-professional social media posts.
"This shows the importance of cultivating a positive online persona. Job seekers should make their professional profiles visible online and ensure any information that could negatively impact their job search is made private or removed."
This also actually mentions that having an online presence is preferred and, if having one, maintaining the professional aspect is required.
- Finally, there's along paragraph about the negative effects alone:
Ponder Before You Post
Learn from those before you – more than half of employers (54 percent) have found content on social media that caused them not to hire a candidate for an open role. Of those who decided not to hire a candidate based on their social media profiles, the reasons included:
- Candidate posted provocative or inappropriate photographs, videos or information: 39 percent
- Candidate posted information about them drinking or using drugs: 38 percent
- Candidate had discriminatory comments related to race, gender, religion: 32 percent
- Candidate bad-mouthed their previous company or fellow employee: 30 percent
- Candidate lied about qualifications: 27 percent
- Candidate had poor communication skills: 27 percent
- Candidate was linked to criminal behavior: 26 percent
- Candidate shared confidential information from previous employers: 23 percent
- Candidate's screen name was unprofessional: 22 percent
- Candidate lied about an absence: 17 percent
- Candidate posted too frequently: 17 percent
So, taken together, it's not how it is depicted in the article. The author, took the liberty to present the facts in a way that appears to be supporting his previous comments.
As you'd have noticed, most of the job application forms do not have a field for social media links / profiles. They are only necessary for relevant fields (example: PR industry), but for an engineering job, it really does not matter whether you have a social media presence or not.