As a Human Resources Professional, it depends on the industry or business, and the nature of the job. I’ve worked in Human Resources in the healthcare and financial industries where checking an applicant’s social media was not performed.

Social media screening is essentially tapping into a job candidate's private life. It can reveal information about protected characteristics such as one’s age, race, nationality, disabilities, gender, religion, etc. which could bias pre-employment and employee hiring decisions, which is why the companies I’ve worked for do not use it.

If social media is included in pre-employment background checks, it is not possible to completely separate truth from fiction. And many states have already passed, or are considering, legislation that prohibits employers from requiring a potential (or current) employee to share their social media.

I am also keenly aware that people pretend well and:

Candidates with high emotional intelligence and good judgment are “usually” those who are able to manage their emotions well, and are able to demonstrate that during the interview. There are also other ways to vet a candidate without checking their social media - such as asking open ended questions to learn more about the candidate, how they handle themselves during the interview, verifying their references, and conducting a criminal background investigation.

If you are being asked for your username and password, it may be a violation of your rights to privacy in your state.