I cannot disagree more ...
There was a time, were beeing on lkdin, tw has been an advantage (fb never was an advantage), but these times are (almost) gone. Since everybody does the same, the "presence" on "social" media in not really an advantage any more. Especially if you are a small company do not waste your time on "social media" focus on technical advantage, focus on ideas, focus on creativity. The absence of a "social media" presence will mystify the results and people will be proud of "finding" something in the "real world", but of course only if you made your homework, only if you are really good. For all the (average) rest "social media" will possibly help for a while.
The internet does not forget, every post, every entry, every question, every answer, possible customers, people who might be interested in you will read it and judge you by what they read, some do really not recognize how they "disqualify" themselves when the post/ask/answer in discussion groups (especially on lkdin).
best regards
Ferdinand