That means LinkedIn profile that identifies you as an investor, perhaps with your ask in 3(3) above as the description; a custom email address (custom email addresses only cost a few bucks); and, if you are very serious, a simple landing page for your investment business, with your contact information and the kind of property you are looking for.  

Hey guys, I am fairly new to the REI world and am currently employed through a direct lender that provides fast, specialized financing for business needs, real estate investment and refinancing of high rate loans.I have been pretty active by going to events around here (NYC) as well as engaging with other professionals in the field via LinkedIn but have not found many people who needs jumbo alt doc loans.

Somebody posted this video on linkedin.

I also was suspect, but asked him to confirm via Linkedin, which I know is his real profile of over 350K followers.

After searching on the internet, on Bigger Pockets and on LinkedIn among many Angel investors, RE groups, crowd funding platforms and private investors, I received many offers.

Also, I did message Ryan Wright on LinkedIn as to the internal issues going on and he was surprisingly responsive, but not sure if he was involved in getting anyone off their butts to get a move on with things.

I read this on Linkedin once. 

@Chen HsuHi ChenI’m reaching out to anyone lied to by this company Here’s my post you can reach me on fb or linked in my Comp info is at the end of my post....David Corbaley’s ‘Commando deception’ - “you’ll get lots of leads in just a few days” they say... nothing but lies!!!

Multifamily:  (I'm pretty sure I saw these stats linked in another thread, but for the life of me I can't find it to give credit to the poster.)  

The backlinks to my site helping my rankings are NOT made by spinning fluff articles all over the internet.My backlinks come from REAL content, from relevant places on the interwebnet:We have a company Facebook Page with links to our siteI'm active on Bigger Pockets forums, member blogs, & BP blog posts, and each time I post/comment my gravatar or signature contains links to our siteI comment on J Scott's blog page, gravatar has links to my siteI comment on Danny Johnson's blog page, gravatar has links to my siteI post Craigslist Ads (NOT spammy) with my G Voice number & links to our websiteI post & comment on LinkedIn every once in awhile, which doesn't have a direct link to our site, but if they click to see my profile, that page has a link to our website.It's not as hard & convoluted as some people seem to think to get yourself ranked on Google & get quality backlinks.