- the concept of ideology is a relatively recent one because the word ideology has become more frequent recently (this is almost certainly false).
- Jesus "wins" (his word, not mine) against the Beatles because the word Jesus is more frequent.
I like the Ngram Viewer, but simply plotting the frequency of words against each other to determine something about culture or concepts is a very weak technique that leads to massive mis-interpretations, as we've seen recently with things like counting the number of times President Obama uses pronouns in his speeches. I discussed the failings of simple word counts as a technique here. To sum up,
- We don't know what causes word frequencies.
- We don't know what the effects of word frequencies are.
- There are good alternatives.