1. The listing is flagged NO to allow internet in the MLS.
2. MLS is not linked to Trulia.
3. The link is there it just missed the feed.
4. Your agent hasn't entered it manually into Trulia.
Ask your agent to check for you.
Please refer to the question below and my answer. There you'll find information that you can forward to your Realtor so he or she can submit your home to the Trulia search engine.
Customer Service Representative