It's used so the agent can make appointments on the houses that interest their clients, promote listings that they have, open houses, etc.

I bought these properties when there is promotion to (a) waive management fees for a year (b) reimburse mortgage expense for one of the properties until it is tenanted because it was not occupied when I purchase it. 

You can expect investors will want a preferred return of 8-12% that is paid out before you as the sponsor get any promote.

I know a guy, but I can't mention him or I'll get flagged for self promotion.

If you are going to promote yourself, then I recommend buying a PRO account. 

I was listening to a Podcast recently, #242, where the interviewee was talking about how he used Facebook (FB) to promote and "advertise" his properties.

Would recommend doing some reading on SEO/SEM so you can promote that business fairly cheaply :)

Sure you pay fees and a promote along the way, but paying the promote (normally) means it was a good deal and you should be happy to pay it!

Sure, some agents know about deals before they hit the market, but that's because they did the marketing necessary to promote themselves and be in a position to have sellers contact them to sell their property."1.

@Randy E.and @Curt Davisplease stop trying to get me to promote on the forums:)  I especially agree with Randy's earlier quote about the difficulty of predicting appreciation.