Well, no reputable dealer will tell you they're for giving up nicotine. Or at least they shouldn't. They're a replacement for burning tobacco and all the 4000 or so harmful chemicals that come with it. Essentially a far safer nicotine delivery system that comes in pretty much any flavour you can think of.
Some people cut down their Nic levels as they go and eventually either stop or just use Nic free juice. However, from my experience they're a small minority. Research suggests about 60% of people who try them switch either partially or totally to ecigs and there is anecdotal evidence of significant health benefits from people with chronic conditions like COPD.
Personally, I've no intention of giving up nicotine. That would be like giving up caffeine. Unnecessary misery for no real benefit. When you take the cancerous tobacco smoke out of the equation, what's left is pretty harmless.
Sorry. Rambling, i know. Been to a pub with about 25 other Vapers tonight. Puffing away all evening...indoors...legally. I can probably count the number of times I've visited a pub since the smoking ban on one hand, so I'm no good at drinking these days. [hic]