As Narissa, Llohuir, Ysylla, Caeth (but joined very much later into Nexus at hero), I had my fair share of immteraction. Think about it, if you are an Imm with limited time, you probably have a couple of priorities, empowerees, followers, cabals, general Thera, quests, etc. There is only so much to draw your attention to.

So my take for good immteractions are:
1. Cabals
2. Leaders
3. Empowerment characters,
4. Followers seeking tattoo
5. Noteworthy, uncaballed characters with good roles, story, well-RPed (you get the picture), etc

So if you are just one of the face in the crowd, you tend to be passed by.

$0.02