One of the things you're going to need to know is how to be a super sleuth on the 'net. Gurus have no shame in spying on other marketers.
It goes on all the time - even in the offline world. One cola company will come out with a cherry flavor and the others line up right behind them to do the same. One fast food burger joint puts out a burger with jalapeno peppers and the rest follow suit shortly after.
Now let me clarify something right now that's REALLY important:
I do NOT advocate STEALING ideas and ripping off people's hard work!
This does, unfortunately, happen to many marketers - and rest assured it's going to happen to you too. To prevent being dominated in the market, you'll have to always be the best at the information you provide. Still, you can get great ideas from spying - and do things better than another marketer or different and make a killing in the marketplace.