If you have 100 Sr. Member accounts in various signature campaigns that pays 0.001 BTC per post, then by posting only 10 posts per day per account, you can easily earn 1 BTC.
that's 1000 constructive posts per day. impossible to reach even if you're a genius with vast knowledge.
and that's not what people would call "easily".
Although it's not easy, I believe that 1 BTC a day could be achieved solely through signature campaigns. By signing accounts in the pay per period campaigns, rather than pay per post, you can earn profits of up to .002 BTC. Let's be conservative and say .0015 per post. That's 667 posts a day. Just over 40 posts an hour if you work 16 hours a day. For someone that is working extremely dilligently and has a very good grasp on reading/writing, I would argue that this is obtainable. Sustainable? Probably not. Easy? Hell no. However, it is possible.