You need to start clicking on the answer question button, Trulia is not a place for you to get business it is a place to help people. Answer questions that you are knowledgeable about and in area you know about.
If you want you can blog advertisements but the best thing to do is just give good information, if you provide good information people will find you when they need you.
The site is also good for link building if you put some good information on your site then put links as you answer questions google notices all links on trulia and rates those links high.
I feel that this site is an opportunity for Real estate proffesionals to show that we are qualified in our field, and good PR because a lot of people have lost faith in our industry.