Rick, 
 
Really nice and useful data about average number of followers / followings, thanks! I'm gonna check the state of the Twittersphere as soon as I find some time :)

The pace of growth doesn't really matter, anymore. We are all connected in an easy to use, easy to read, effective way. I never thought that it would work, but twitter has revolutionized communications allowing everyone on the planet to communicate regardless of city, state, political orientation or other

Great data report, thanks for all the wonderful insight into the continued evolution of Twitter as a community and communication medium. I was surprised to see that over 80% of people using Twitter have less than 100 followers and are following less than 100 people. Do you think that is where the best value from the service comes from? Do you think there will be a time that a twitter users with tens of thousands of followers will be penalized or viewed as spam instead of authoritative as they are now? I mean it's not like they can really be connecting with that many people, and at that point it really becomes something more like a short broadcast email doesn't it? Curious what other people think about this. I myself have about 850 followers and I am feeling like I need to "trim the fat" a bit and optimize that grouping because I am sure there are people in there that just aren't brining much to the table for me. Now if I only had the time to do it.....

Great info. This totally connects to a prediction by economist Jérémie Bertrand who compares Twitter to a Ponzi scheme (sic!), where the currency is user attention: http://www.hypios.com/thinking/2009/11/18/is-twitter-a-ponzi-scheme/

One thing that is interesting is that Bertrand's theory explains and predicts the link between growth of number of people followed by those who are on twitter and a declining number of users. If Bertrand is right, the fact that people follow more users is not good for twitter's health, but quite the opposite. Because if you follow too many people, the attention accorded to each tweet goes down. So the future of twitter probably lies in following less people & in better filtering rather than in massive following.

To piggy back on what Matthew just said, I wonder if it's not the increase that is causing the decrease.  
 
I've found that as I follow more people, I've had to get smarter in how I manage the feed from those people in order to get the same value. This has included better use of Tweetdeck, filters, and dropping some who take over my feed with a post every 10 minutes. 
 
I can see the masses having little tolerance for this additional work and thus spending less time with the service. 
 
Thoughts?

RE: Chris 
 
Thanks for the additional comment. I have to agree with you. And that is pretty much what I was getting at. The larger the universe gets the more unwieldy it becomes, do I feel I get more value as my group gets bigger? So far I am not so sure because it seems to me that there is a much tighter group within that following that consistently participates with my new content that provides me the most value from it. That additional broadcast potential is just an added bonus as far as I am concerned.

Thank you for this great, informative report. I will surely talk about this Twitter report on my blog.

Matthew, Chris, you guys have raised an interesting issue. In my own case, I'm trying to balance the valuable reach of a large network w/ the high signal/noise ratio of a small network. I think some of the tools/features Twitter is adding help in this dept. Twitter lists are a great example. I check specific Twitter lists a lot more than I check my full Twitter feed, and that's because the lists are more relevant and interesting to me.

The number of Twitter followers one has is a useless metric when described in a vacuum. Only when compared with those one follows can it be useful. 
 
There are many people who have thousands of followers yet they follow even more people. There's no reason to take people with 'upside down' numbers seriously. When some one has twice as many or more followers than they follow, they are more likely to be a better source of information or an industry leader. 
 
Twitter will continue to experience sharp increases and decreases in most metrics as people figure out how best to use the service or whether to abandon it. Just because it works for some, doesn't mean it's for everybody or even a panacea.

Twitter's novelty wears off after a few weeks, so I do not think it will be as big a success as once everyone thought it will be!

I guess this is normal. I think there's also a lot of people that registered during the peak, linked with a couple of friends, and never sent a tweet after that. I guess 3% sounds more like a sustainable (at least for the next year) rate of growth.

Wouldn't median figures be more illustrative than averages for account usage? After all, Ashton Kutcher and Oprah are HUGE outliers that skew this data significantly. If you take out the outliers, account usage may be roughly the same as in March.

Could someone please explain to me how the average number of people a twitter user follows and the average number of followers a twitter user has are different numbers? 
 
To my way of thinking, you have a finite number of twitter users, and a certain number of people following one another. The math for the average number of people users are following, and the average number of people following a twitter user is the exact same math. Where am I falling down? What am I missing?