There are seven basic strategies that Twitter users adopt:

1. Reciprocate any follows. This can be done manually, or automatically by using a service such as socialtoo.

2. Look at new followers and decide whether you want to follow them back. This is the most common strategy, which allows people to decide based on a range of factors whether to follow back.

3. Turn off follow notifications. High profile Twitterers simply follow people they know, and choose not to be notified who follows them (sometimes simply because their email inbox gets clogged by follow notifications).

5. Follow people because they are interesting and/or likely to follow back. People follow Twitterers because they have something interesting to say, but they also usually factor in how likely they are to be followed back (judging by the person’s follower/ following ratio).

6. Indiscriminately follow others, and only continue following them if they follow back. This is used by people who want to gather a large number of followers.

7. Have a protected profile. This requires the Twitterer to respond to requests and give permission for people to follow them. In this case Twitter can be a true friend network rather than open broadcast.

All of this creates an environment of ‘asymmetrical follow’ that is fundamentally different from the symmetrical relationships of social networks such as Facebook, that require people to approve friend requests.

The critical issue that drives these strategies is the reality of limited human bandwidth. Once we follow more than a few hundred people, it is impossible to keep across the posts, let alone who is making them. Those who are able to spend a large proportion of their day in social media activity can be engaged in broad and diverse conversations – others can only dip in to the stream.

As such, underlying the strategies above is a choice: do you try to limit how many you follow, in order to follow your friends and/ or the most interesting people better? Or do you go for a full stream of Twitter, which you can manage in various ways, but still means you can only skim the surface?

MediaShift has published a very interesting article titled Dealing with Friend Inflation on Twitter, Digg, going into some of the strategies adopted for Twitter reciprocation. Perhaps more interesting in the article is the situation in Digg, where power Diggers need to rely on a core network who are likely to reciprocate their Diggs.

Neal Rodriguez, an SEO specialist for Nielsen Business Media, has managed to propel 179 submissions onto Digg's front page as of this writing. In a recent phone interview, he told me that it isn't the number of friends you have that helps get content to the front page, but rather the number of active reciprocal friends. Digg, he said, only allows you to send "shout outs" (messages that push your submissions) to a very limited number of friends, making it essential to weed out the non-responsive, inactive Diggers.

"When you push the 'share' button there's a selection that says 'shout to all' and it'll allow you to shout to everybody," Rodriguez said. "But the end result is it only shouts to a small proportion of that whole list that's available for you to share with. If you look at your recent activity -- and if you shouted to all -- if you have about 200 friends it only went out to 50 people, or only 26 people."

So it's imperative that the power Digger maximize the chances that those 26 or 50 people are ones that will be sure to Digg content shouted to them. This means that you have to choose your friends carefully, looking for tell-tale signs that they are more than just casual users. When Rodriguez first started on Digg, it was a matter of observing the other power Diggers and pinpointing which of his friends were most consistently Digging his submissions.

A couple of years ago I wrote a post on Uncovering the structure of influence and social opinion, which looked at research on how a small number of people are very prominent in submitting the top stories on social content sites such as Digg and Delicious. The changing dynamics of reciprocity in messaging are shifting this process. However it remains absolutely embedded in reciprocity – top Diggers are top Diggers less because of the stories they submit than because of their network, who implicitly support each others submissions, giving them critical mass and visibility.

What we are seeing in the rise of Twitter and the changing dynamics of social content sites today is the critical role of reciprocity and the rise of asymmetry. Analyzing how reciprocity is changing will give great insights into how the social media landscape will change over the coming year and more.

This points to what I first wrote six years ago in Living Networks, and have often restated:

“Blogs are not necessarily important individually, but in aggregate they are massively powerful. The “blogosphere” pulls together what millions of talented people around the world are discovering and thinking. Collectively, blogs enable us to collaborate to filter and uncover the most worthwhile news.”

The Guardian is the latest to say Memeorandum runs rings around Google News.

“Memeorandum is embarrassingly better than Google News. Google reckons that the more coverage a story gets, the more important it is. Unfortunately, broad coverage takes a long time to develop, so Google News can run hours or even a day behind Memeorandum. This is fine for casual consumers, but if you're a news junkie – or a journalist – it's hopeless.”

Memeorandum was heavily tracked by political bloggers during the election, and today a host of prominent politic bloggers (who probably count as the most extreme news junkies in the worlds) have linked to this story with their own compliments. See: The Moderate Voice ("in case you don't know about it... you need to"), Buck Naked Politics ("It's certainly the first place we look to stay on top of what's happening"), Outside the Beltway ("Memeorandum has long been my first stop to see what stories people are buzzing about."), and The Impolitic (I've long considered Memeorandum to be an essential blogger tool for checking the daily buzz... If the media was a true meritocracy, then Gabe would rule their world")

It’s interesting to me that both Memeorandum and Techmeme, the technology blog aggregator par excellence in a crowded field, still don’t get a lot of traffic. The visitors they do get include the most influential and switched-on people in politics and technology, but for seem reason they’ve never hit the mainstream. It makes me think there’s still an opportunity in this space, despite many failed attempts so far.

Gabe Rivera, the creator of Memeorandum (and sister sites Techmeme, WeSmirch and Ballbug), spoke at our Future of Media Summit 2007, on our Influence Networks panel, offering some great insights.