I've been blogging here for nearly a year with various peaks and valleys of frequency.
The content of these writings? A mixture of one part self reflection and one part shares of other internet musings (videos, other blogs, snippets). At start, I was posting regularly at least once a week if not twice. The longest I've gone between posts is two months.
The cause for these less frequent postings is likely because of time and writer's block.
But in a recent book talk for Mitch Joel's Ctrl Alt Delete, Seth Godin thwarted the entire notion of writer's block by noting that "you can always just write how you talk." The term "writer's block" itself was only first coined in 1947 by Edmund Bergler. And considering that the vast majority of writing is non-fiction based (bloggers, personal journals, I guess you could also lump in Facebook messages and posts here), Godin is probably right. For the sole purpose of getting the first draft or the first arrangement of words out, it's helpful to simply speak on the page.
No one wakes up in the morning and thinks to themselves "You know what? Today, I think I have talker's block."