Ultimately, the idea of blogging as a task requirement in the conventional pedagogical model does not work. I fundamentally disagree with requiring students to blog in the following circumstances:

1. Tying the task of personal blogging to external validators not of the bloggers' own choosing;
2. Externally imposing learning outcomes not negotiated with these bloggers; 
3. Requiring student bloggers to blog in the open for grades without having the educator fully participating in these same blogging processes and guiding them as an active role model;

There are a series of assumptions that underlie the nature of autonomous blogging as I see it. I have seen many learners blog to the task at hand, or blog for establishing and building a network, or blog for oneself, deciding at some later time to blog in the open for a select few. There are many different reasons for choosing to blog, for choosing to put one's ideas out there. The nature of the power imbalance often in place between instructors and students serves to objectify autonomous, personal blogging and strips it of its intrinsic value.

You cannot get students to blog. Period. You cannot convince a single student to invest themselves into a long-term blogging journey if the educator is trying to convince them to participate with simple "carrot and stick" motivators. Students should instead enter into a conversation that encourages them and reassures them that their personal investment is worth the effort. This conversation should be moderated by a learning companion, by a mentor who is an active blogger, who is completely convinced of the significance of long-term sustained personal narrative as an end in itself, as an incredibly important tool that guides and shapes oneself over time, through transitional events, through courses and programs and seminars and conferences. 

Such a mentor would model the journey, model the processes, and model both the serious sense-making activities and the rehearsing and play-building and celebrating. Students need to experience the mentor's blogging firsthand if they are to be convinced that the blogging journey that starts with a first step is worth embarking on at all.

It is the blogging tool (and related network learning tools) that ties learners together and threads personal identities over the lifespan. Encouraging learners to start a blog and sustain their personal commitment to blogging is best done by serving the individuals' long-term core identity needs, not the short-term goals of making the grade for the course in the short-term.

The thing is, blogging as I am referring to it is fundamentally different from cohort-based interactions within an asynchronous forum.

There are many who assert that sustained autonomous blogging in the open without the benefit of a guarantee of a cohort or circle of peers to comment and encourage further contributions is a seemingly pointless exercise ... it seems even more pointless in the absence of direction or prompts by the moderator about what is to be discussed, what the group is going to work on together, without the leadership of another. Blogging seems pointless and far too subjective if it is lacking a method for formally assessing the activity in terms of learning outcomes.

So it seems. So, many educators and their learners can't or won't contribute to their own blogs without some possibility of reciprocity and sharing by others, without some form of external validation or sense of externally imposed purpose. The extent to which we are dependent on others' comments and feedback or on meeting explicit goals determines the extent of personal commitment to using the blogging tool as a lifelong learning tool. Doesn't this bother anyone? Doesn't it bother anyone that the majority of things worth learning in a formal setting is what is in fact externally imposed?

So I come back to the question: should we get students to blog? I would answer no. There are plenty of other tools for enforcing compliance among learners and reinforcing extrinsically-motivated learning. Leave the blogging tool alone for the autonomous bloggers and their peers who voluntaily engage in lifelong learning.