People have long said that they turn to LinkedIn only when they are looking for a job.

I've been hearing that less these days. In fact, when friends, clients and others bring up the professional social media networking platform, it's more along the lines of them knowing that LinkedIn is important even if they don't yet know how to engage.

Indeed, LinkedIn has been growing in popularity. At a LinkedIn conference earlier this month, the CEO shared that the platform has 645 million users, an increase of 70 million users over last year. One argument for joining LinkedIn or re-engaging on it certainly is the fact that more and more professionals could see your profile and connect with you. Here are four other reasons to not just be on LinkedIn but to be an active participant.

1. People get hired through LinkedIn.

At that conference, LinkedIn CEO Jeff Weiner reported that more than 4 million LinkedIn members were hired through the site in fiscal year 2019. He said that the 32 percent year-over-year increase was partly due to investments in artificial intelligence that bring better job prospects to both members and recruiters.

2. Your profile is your 21st century resume.

I still see people dust off the resume when it's time to apply for jobs, and that's necessary and important. But people who might want to do business with you or hire you, don't necessarily wait until you come to them with a resume. There's no telling when someone might check out your professional profile because they have you in mind for something, so you have to be ready 24/7.

Make sure your LinkedIn is up to date with your latest promotion, career highlights, work samples and more. It will make update that old school resume much easier when the time comes, too. 

3. You have a ready-made `blog' audience.

If you've been looking for a way to show off your subject matter expertise, you could start a company blog, or you could write articles on LinkedIn. Both are excellent ideas. But LinkedIn has its advantages -- a ready-made audience of all of your connections.

4. Your profile -- or lack of -- is your brand.

What you present on LinkedIn, or anywhere, is your story and your brand -- and it speaks volumes. So if you are on LinkedIn, you should really be on LinkedIn, with a headshot, cover photo, up-to-date headline and experience and more. Having sparse  information isn't helpful to your audience, and you are passing up important career storytelling opportunities.

Bottom line: You are what you communicate to the world, so make sure you tell your whole career story on LinkedIn.