It really depends on what your time is worth.
If you could be interviewing first time home buyers instead of spending that time at the keyboard you should be where the buyers are.
However, if you have consistent slack time, or you have purposefully focused on this, and similar, media resources and will commit time to it, just like any activity in which you commit to, you will see results.
I would advise you conduct you own research for your specific area to determine if Trulia is the best venue for your purpose. You may discover Trulia to be a minor player in your geographic area. Secondly, understand who the buyer and seller is that participates on Trulia. Never let the convenience of social media place a barrier between you and real live people.
Best of success.