Blog Survey

So I'm creating a survey for my TOK kids to figure out what works, in terms of our classroom blog, and what doesn't. It's a bad time of year with IB kids, Internal Assessments, External Exams, end of year burn out, so they aren't using the blog nearly as much as I would like to... so here is my question...

Many of my students tell me I should increase the requirements of how often they should be posting/commenting (1 or 2 x per week is the suggestion) and I initially agree. But here is my dilemna...

How do I motivate students to use the blog yet make it meaningful. I'm not interested in forcing students to post/comment but I know that external motivation may be what is needed. There is little doubt that those who used the blog understand the class better -- its all about language and the ability to justify knowledge claims -- so students who write and discuss more really work through the struggles and really get TOK and can utilize the skills. So what do I do...?

I'm in the process of getting their opinions... I guess that is the beginning of teacher research, but I'm assuming that there is an enormous amount of bias in that "qualitative" research. Sorry... its the scientist in me. Get rid of the variables... control... control... take data... analyze data... This is all an adjustment, but a good one. So back to my problem...

What do you think? Do I force students into blogging or do I find some other form of motivation? This class is not grade intensive and is meant to be a compliment to all of their other courses, not a huge burden, so I struggle with upping the requirements because the reality is that it will never be at the top of their priority list in terms of HW, etc. Nor do we want it to be. So how do you push students into being the best thinkers possible by tapping into an intrinsic motivational button that I can't seem to find in seniors at the tail end of high school...?

sorry... a bit frustrated, confused, yet super interested, curious, and motivated to figure it out.