Would it be a good idea? Would it be easy to promote/advertise? How would revenue flow in this project? (Adsense?) Thanks.
my only suggest would be to make it a niche site, not a generic site (like digg). You'll have much more success in a niche than going up agains digg. Example: Like golf? Do a digg site just about golfing news/tips/deals/etc.
I'd personally look for the next big idea instead of trying to copy someone elses. That doesn't really help you though, sorry.
It would be easy to create in the sense there is now publically available "digg" scripts. But yeah. stick to a niche.
I'd imagine if you wanted a good niche, you'd need to go more specific than what Digg or netscape are doing, like for gaming, mmorpg, or movies/etertainment you could go with bollywood news, or maybe local bands and music if you wanted to go really niche. Stuff of that sort. What is your end goal of the site? Something to make some bucks while the going is good? or something with some long term viability? I'd be skeptical about putting too much into it if you were looking to actually compete with Digg. I mean, Netscape seems the most viable competitor to digg, and they allready have a ton of "channels". I don't use them myself, and can't speak to how well they are doing, but given the fact there are many stories with 10, 15, 20 votes on them that are front page, that doesn't seem terribly exciting to me. Not saying you can't do it because netscape can't, but it's a david and goliath battle, Digg's got it cuz they made it, and when somebody like Netscape can't do it paying people, it sets the bar pretty high for somebody starting out fresh.
I think if you have to ask questions like "is it a good idea", and "where is the money coming from", it's not a good idea. Good ideas are relative to your level of experience and ability. If you have no idea how to monetize a social bookmarker, or how to promote it, I think you'd be better off starting something different. There are a few niche social bookmarkers around (even one for internet marketers: http://PlugIM.com), and I haven't seen any that are really taking off.
Would it be a good idea? No Would it be easy to promote/advertise? No In order to make a successful site like Digg you need to get a ton of traffic coming to your site about that niche. That is not an easy task and take a ton of time, planning, and a nice budget.