I could be wrong, but I think this thread took on a different meaning than the original poster intended. What I read was, which fragrances received a lot of hype/praise, only to disappear soon after--nothing to do with a fragrance's longevity.
I think a history of a lot of fragrances are cyclical. I know way back when, Piper Nigrum got a lot of heaping praise from Paul G and myself. Then it died down the less we posted.
I do agree Idol was one of the more hyped fragrances prior to coming out, something which I attribute more to certain outlets "pre"-selling it, and it just never lived up to my expectations and I sold it away within a few months.
Salvador Dali's Laguna is one that had quite a following, and it may still rank as being under-appreciated, but I don't see too many threads inquiring or dedicated to it any more.
I thought about writing a post looking back at the fall of 2002, when both Cuiron and M7 came out. These two fragrances were the topic of many discussions. I bought Cuiron immediately, falling in love with it. M7, not so much so; I had numerous samples of it and just couldn't get into it. Reading the most recent review in the directory got me thinking that I've definitely seen, or sniffed, my taste, er smell, in fragrances change over the year, and have a bottle on the way. These two fragrances, now over 6 years later, stand as true originals (as well as the test of time)--there have been too many similar fragrances launched over that particular time frame, but these two remain, for me, as fairly unique.
Stardust has had a cyclical life as well. I recall Ali discussing how much he liked it way back on the Yahoo! boards. It became the topic of numerous discussions, and seems to have recently been resurrected about a year or so ago when it became almost impossible to find and prices were outrageous. Now, it appears it's fairly easy to acquire at a modest price. So, in a sense, it seems the popularity of discussion on the boards is somewhat dependent on whether very few have tried it, or, as it became more readily accessible, more people purchasing it.
There's always going to be the flavor of the week, especially now when it appears the number of fragrances to be released has skyrocketed. I know there a number of other scents that were high on the buzz factor, only to limp away silently into the night... But the one scent I saw die a death faster than others (without the buzz), was probably Calvin Klein's Crave. That was DOA.