I used to jump on many marketing alternatives and felt if I got $2 back for every dollar I spent in work I was doing well.  I then started tracking my number properly and quickly realized I need as a minimum a 4 to 1 ratio not a 2 to 1.  This has made it easier for me to yes or no a option like this.  When I talk to the rep and tell them for every $500 I spend per month, they have to guarantee me at least $2000 worth of work per month, or I want the service for free.  At that point the rep usually backs out.  I also won't sign a year long contract, I tell them if their product actually works they should be comfortable for me to be on a month to month basis.

Remember if they have no skin in the game it's easy for them to tell you how great it will be, but if they have a stake in it, the game changes.

Also it's on you to do some research, some forums work amazing for 1 industry but not others.  Understand your needs and who it's reaching.  It's also on you to use it to it's capacity.  The site isn't going to do the work for you and they shouldn't because they don't know you like you know you.