It's simple to use. Uncluttered. Makes your communication with your friends easier.
We use the term "easier than" because only you can decide if it is better. I haven't used dreamwidth so no comment. Twitter and Facebook are gigantic successfull companies doing great work. For the "communication with your friends"-wise our product is easier to use.
Your ROI could be easier and more direct communication with your friends. On Tusulog you cannot broadcast to all your friends at once, only to the specific group you choose. So you don't worry about "if I post this my mom/boss/ex may see too!". This may not be a problem for power users but most people don't know how to tackle those complex privacy settings.
If you join and have a few friends over there believe me you'll say "I wish all my friends were here then everything become much easier".