I haven't gotten many answers to this question, but most tend to lean that they are not tech companies. The prevailing attitude towards them is that they don't treat their developers as "first class" and that generally underpay them, relative to the average developer salary in the rest of its job market. I argue that digital agencies ARE tech companies because they would not exist without the internet. Doing work on websites is always involved in the transaction for their B2B model. So what is your view of digital agencies in the context of tech companies?
