I think my PKM is pretty similar to yours in respect of what comes in via my RSS feed. But I think it is less quantifiable if the source of the information is something other than that. I think the process differs depending on the situation. Like Stephen, I tend to write in response to something I see, but I also address things that exercise my mind/give me sleepless nights. Writing about something helps me marshall my thoughts and get clarity or closure. Sometimes putting an idea into writing helps me see how ludicrous or unworkable it is - hopefully I spot that before hitting the post button, but there's no guarantee!