As I’ve already noted, I’m not a blogger. But I’m not going to let a little thing like that stand in the way of explaining my unifying theory about the nature of the blogging business.

It all started when my old friend (and I use the term old advisedly) Ben Casnocha called me up to ponder the following question:

Is there a natural limit to the size of a particular blog’s audience? In other words, does the type of content you provide impose some sort of ceiling on your potential readership?

I’ve actually been pondering this question myself, and I’ve come to the following conclusion:

The natural limit on the size of a blog’s audience depends on the degree to which the blog
1) sticks to a particular topic, and
2) creates a cult of personality around the writer.

Here’s why the non-intuitive reason why these limits exist. In a world of endless feeds, each blog reader will eventually end up running into a physical limit on the number of posts he or she can read per day. Even someone who devotes every waking minute to reading blogs cannot possibly read more than a miniscule slice of the new posts that appear–and most of us devote far less time than that.

As a result, every blog reader will eventually find himself forced to winnow his feeds, to focus on those feeds that are richest in relevant content. The two basic measures we can expect him to apply are:
a) Does the post cover one of my preferred topics?
b) Is the post from someone I like and want to stay connected with?

The First Law of Blogging states that the more topics a blog covers, the lower the percentage of posts that will match up with the preferred topic set of any particular reader.

I may be interested in both entrepreneurship and country music, but many readers who like posts on entrepreneurship may be indifferent to negative on posts on country music and vice versa.

As with mutual funds, the best practice is to stick to your particular “style box” and let the individual reader or investor pursue their personal portfolio diversification plan.

Mutual funds also provide a useful analogy for The Second Law of Blogging, which states that the other way to build an audience is to cultivate a cult of personality. Berkshire Hathaway doesn’t fit into any of the usual “style boxes,” but Warren Buffett and Charlie Munger are so successful and brilliant that no one cares.

Similarly, some bloggers do such a good job of projecting their personality through their blog that their audience tunes in just to keep up to date with an old friend.

If you don’t believe me, take a gander at the Technorati 100:

In the Top 10, we find:
1) Engadget (focused)
2) Hexuncom (personality, I think–can anyone translate?)
3) BoingBoing (focused, though the personality of the contributors adds)
4) Gizmodo (focused)
5) TechCrunch (focused, though Mike’s personality mattered in the early days)
6) The Huffington Post (focused)
7) Lifehacker (focused)
8) TodayLink.ir (focused, I think–can anyone translate?)
9) Daily Kos (focused, though Kos’ personality mattered in the early days)
10) PostSecret (focused)

All of the top blogs are either focused, build a cult of personality, or both.

The maximum audience of a general blog like Ben’s depends on the extent to which he is able to build a Cult of Ben. Meanwile, a general blog which does not generally delve into personal details and stances like this one is even more limited.

Ultimately, I realize that the audience for this blog is limited, but I’m willing to live with those limitations. If you aren’t, you should focus your blog and start building a distinctive voice and personality into your posts.