I don't know how every ticker I've followed met it's end since I eventually don't bother with them after they've not traded for a few years. That's also about the time they either get revoked or delisted.
You would think, just as you're thinking about INOL, that they'd have been picked up and used for some other company's business plan. Obviously, that's not always the case because the list of delisted ticker symbols is verrrrrry long.
Maybe it's because there are more ticker symbols available than can be used.
News 
Market Data 
Discover 
