In a recent colloquium, the speaker's abstract claimed they were using machine learning. During the talk, the only thing related to machine learning was that they perform linear regression on their data. After calculating the best-fit coefficients in 5D parameter space, they compared these coefficients in one system to the best-fit coefficients of other systems. 

**When is linear regression *machine learning*, as opposed to simply finding a best-fit line?** (Was the researcher's abstract misleading?)

With all the attention machine learning has been garnering recently, it seems important to make such distinctions. 

My question is like [this one][1], except that that question asks for the definition of "linear regression", whereas mine asks when linear regression (which has a broad number of applications) may appropriately be called "machine learning". 


  [1]: http://stats.stackexchange.com/questions/254176/what-should-be-called-a-linear-regression