I'd gone back to review that thread that you started on the logline, just to make sure I wasn't confusing the two. But the premise is more a tool for the writer in developing the story than for putting out feelers to potential readers. (Although the premise can be used to sell a story, in Hollywood at least.)
Yeah, what I had read, though, was "share your premise"… because of that story that Neil Gaiman has about that guy that swore he had a kick a$$ premise, then shared it with Gaiman and it was something like "Man travels back in time and kills grandfather."
Basically, what i have read is, if you are comfortable sharing your premise with others who are more experienced, then you might get some insight as to whether it is worth writing or not. Being relatively inexperienced myself, sharing my 'premise' with you and Nimue and Devouring Wolf really helped me to hone in on what was important, and what I wanted to do with the story, and how to inject more 'inherent conflict' by bouncing the idea off of a few people. It is not perfect yet, like I said, what my log line post did was more give me a concrete 'concept'… now I'm trying to work on narrowing it down even further into a solid premise or theme.