A combination of reasons: - Linking to a specific page might not work for many setups such as those who use an external program to open the pdf - The tweet is

A combination of reasons: - Linking to a specific page might not work for many setups such as those who use an external program to open the pdf - The tweet is a lot easier for many people to digest who may otherwise pass on reading (even a section of) a 40 page pdf - The full original source (which often I would prefer to link) was easily available in the tweet, so it wouldn't be hard to find for anyone who wanted it - Coming up with a suitable submission title (80 characters or less) for the PDF was difficult as I wanted it to include information about more than one of the sections (such as both remote control + lane changing)