I do offline campaigns only when I'm really bored or there is potential to make some serious cash (or both), my favorite method being fliers-nothing has converted as well for me. Apart from noticeboard posters and the like (but these are often torn off the board by some sadist or the other). Fliers you really shouldn't just play around with-they need to be targeted, just like PPC. This means you don't distribute forex fliers outside grade schools, and it's always, always best to involve some incentive or special offer or whatever, or there will be no motivation to visit your site.
And yeah, so far it's been an offto link on the fliers/posters/word of mouth that has led to a blog landing page, it's worked quite well but a campaign of this scale certainly deserves a domain of it's own-it's the least kind of respect you can give.
The energy niche I plan to distribute wherever (and this may sound sexist) it's more likely to be seen by men, since women are likely to find something like this interesting and forget about it just as soon...not worth the risk IMO.
A poster or two in hardware stores, at my local club, and I'm even considering roping my electrician into this, since he visits a lot of homes and can easily persuade people into investing in something that's beneficial, plus I can offer him even $5 a sale and he'd be delighted (a dollar goes a long way in India). Plus the sneakiest way - putting up posters around the electricity board here, it just doesn't get more targeted than people hurting at their electricity costs while paying their bills

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I need to give this some more serious thought, but it sure is gonna be a biggie when it starts out, the market is near-endless and hungry for something of this kind. Can't wait till it comes out.