I kept a Livejournal blog with a mostly political bent from 2001 to 2005. After two years off, I continued with blogging for a while, but ultimately got discouraged and quit. Since then, my writing has been defined - and limited - by the prominence of short form social networking. Those aren't enough for me and they don't play to my strengths, so 'here I go again.'
For me, writing is a one-step-at-a-time process that starts with simply getting words down and not obsessing too much over meanings or inclinations. Additionally, long form entries allow greater nuance. I'm not saying nuance is impossible to glean from short form, but I'm not in the business of trying to distill cleverness down to the most economically sized nugget, all of the time. I like digging around with ideas until I come across cogency.
I don't have set topics, but clearly politics and pop culture are the two on my list at the moment.