The proper use of the word via is in relation to travel. E.g., "I flew from Dallas to NY via St. Louis." However, it has become fairly accepted to use it interchangeably as explained by Phil.

When you limit the use of 'via' and 'by' to refer to a method, they are synonyms. In this sense, 'via' = 'by means of', often shortened to 'by'. Refrigeration is a method: He cooled it via refrigeration. / He cooled it by means of refrigeration. / He cooled it by refrigeration. Consulting is a method or process: She helped via consulting. / She helped by means of consulting. / She helped by consulting. Often you can drop the 'means of'. But be careful because 'by' has other meanings: He cooled it by Bob. (here, 'by' means 'near', Bob didn't cool it) She built it by building codes. (conforming to)