1 b) Answer...

I lied, none of them describe a blog, but some older self-writing technology.

1. The first one describes the ancient hypomnemata -- personal notebooks used by the ancient Greeks and the Stoic philosophers to “keep personal records and fomulate opinions about the experience of the self…. This new technology was as disruptive to ancient Greek society as the introduction of the computer into private life today. The hypomnemata served the growing cultivated public in many ways -- as account books, public registers, guides for conduct, and individual notebooks serving as memoranda (archiving)." (Wikipedia; Michel Foucault, Self Writing)
2. The second one describes a modern diary. (Wikipedia)
3. The third one describes the custom of pamphleteering dating back to 17th century. Pamphleteering was especially made popular after the perfection of and the widespread use of the printing press. The practice of pamphleteering was especially influential in the 18h century American Revulution to distribute news and ideas widely and polemicize the issues of the day, especially to spread the word about the benefits of independence from Britain and for recruiting the American guerilla forces that would eventually fight the British. (Wikipedia)

2) What is a blog then?