Yes i agree keywords play important role in this.We can rewrite same articles again n again with different keywords.I think that will work instead of polluting articles and contents that already in the internet.
Unique content is important but you should also have lots of traffic then ad placements maters with high paying keywords too! so you have to concentrate on those things!
rewriting the same articles with different keywords is polluting the internet with garbage. You have to think differently. Think "what do users want to see that is unique". Not "how can i create some crappy article that happens to have a unique string of keywords". Make pages for users, not search engines.
Time is without a doubt the most frustrating aspect of working on the web. You aren't going to make money right off the bat unless you have money to spend for advertising. So if you think you will be making $50 a day in adsense after a month or two you will be very disappointed. Even good content still requires time (i.e. At least 6 months to a year depending on the niche.) in the world of search engines.
I suggest you to don't use RSS2BlOG script. Just write original article that provide useful information to users and see how your adsense money tree grows. It will take some time and continuously efforts from your side and be sure you can make 1000$ a day. Believe me, Its true.