I have introduced a Site membership card
Basically members pay money to get the card, then can be used to get discounts on services, meals and site events.
I also introduced a Points Make Prizes
ranking and I used the "Karma" component to add points
The more members add to the site the more points they earn
This month I got 50+ new reviews, and 2 new listings
It does take a bit of time about 10 mins per day but my site is getting a lot more ideas added and the cost is very lowhttp://www.dalianxpat.org/index.php/en/dalian-life/dalian-living/extra-card