I like the concept of this idea, however, I have young crafty children who often steal my phone and perform all sorts of shenanigans.

My kids can open my storium (which is always open in my internet browser) and make it look like I am a posting fiend. (This hasn't happened on storium-yet- but they've certainly made all sorts of facebooks posts on my behalf.)

The other thought is sometime I have enough time to read posts, but not always time to respond until a day or two later. It would appear I am just ignoring activity, while in actuality I may have become busy in real life, am doing research for a storium response, maybe my internet went down (I don't always have the best connection and have one provider available in my area), or I have lately had issues posting from my phone (I submitted a ticket on this) but can read all the posts.

Maybe instead of a "last online" there was a "last active" option.