I mean that if you are backlinking with the keyword "how to make money online" for an example. And its going fine. But then you build backlinks with the hyperlinked text "make money online" (a shorter version) in an attempt to also dominate that keyword. Will that make Google confused and slightly drop the rankings for the other keyword? It seems to be happening to me. I start with the longest tails ones and then shorten them but the rankings then decrease. What I did then was to go back to building backlinks for the long tail keyword and 30 hours later it was back to normal.