It's been a while since my last visit to the Gembira Loka Zoo (They now have an official website too). I believe my last visit was more than 10 years ago. It must have changed a lot compared to my last visit. Probably someday i will go there to have a look what changes they have made in the last 10 years.
Lately, they are doing what people known as image branding. They have joint cooperation with other vendors to paint their promotion pictures in other's cars, for example taxis, buses, and many public transportation. These transportation vehicles runs across the city for about 8-12 hours a day, so people will eventually sees them and makes them wonders and then decided to go to the zoo. I think this is a brilliant concept to (re) introduce something to public. Let them be curious about something and they will come after you.
One note about their website is that they lack of consistency and updates. For such public services, you must update your websites frequently to let other people know what happened inside.