I read web text by highlighting it. Not all the time, but often enough. The paragraph I'm focusing on, that's the one I've dragged my mouse over, and I might bring it down to a sentence if it's sufficiently insightful. I'm thinking about many things, and this is a way to help myself focus.
But, when I do that, the New York Times website seems to think I'm asking for it to define things for me. It can define a word, but asking for it to define a paragraph blows it's little mind.
I know there's a means to shut this off by telling your machine that lookup.nytimes.com or something is 127.0.0.1. I don't read NYT stuff enough to make this worth my while. But maybe someday soon.