The Half-Life Of A Tweet
Think of message relevance in terms of "half-life" and durability. The half-life of a social media message is the time it takes for the message to begin losing relevance. The durability of a message is how long it takes for it to fade completely from view. If you give this concept careful consideration, you can create the right messages for the right audiences based on your predictions of how long the messages will last in each channel. Match the social media message and its expected duration to the appropriate online channel, and over time, your audiences will come to expect different types of communications from your brand on each channel.
At one end of the message durability spectrum is Twitter. The average Twitter message half-life is about four to six hours, with average durability of less than a day. On rare occasions, if the message value is high enough for strong community pass-along (i.e. re-tweeting and "via @___'s"), you might see durability extended by an additional 6 to 12 hours. Twitter is a great channel for immediate, fast-action messaging and nearly real-time customer support.
Next on the durability spectrum is Facebook. Branded Fan Page Wall posts appear to have an average half-life of one to three days, with durability of three to seven days. Fan Page updates (which function like direct messages to fans via their Facebook inboxes) have a shorter half-life, but a longer durability than Wall and Discussion Board posts.
Why? Because even if initially ignored, Fan Page update messages persist in the user's Facebook inbox until either manually deleted or pushed sufficiently far down in the queue by other messages.
Comments posted on third-party blog posts vary widely depending upon the reach of the original blog post and position of comments. It's important to post early as most blogs present comments in time-sorted order.
The half-life and durability of blog posts may be a week or even several weeks -- even despite the fading popularity of blogs as more and more people abandon "push" RSS Readers to adopt "pull" channels such as Twitter and Facebook. You can always amplify or highlight a new blog post via more immediate channels such as a Facebook page or Twitter account.
And, remember, on blogs, more so than in probably any other channel, copy quality counts. Information shared via your blog, which is either exclusive or controversial increases the likelihood of extending message durability.
Wikipedia is at the far end of the message durability spectrum because the content is largely accurate and relevant and is aggressively indexed by the search engines. Just make sure your Wikipedia content is of high quality and accurately sourced, or it will likely be rapidly removed by the volunteer page reviewers, who are vigilant in stamping out blatant PR flackery.
We came up with this spectrum after several years of research and experimentation by our team at Spring Creek Group, but it isn't necessarily definitive. Experiment with analytics to understand the unique half-lives and durability of your own community outreach and customer engagement efforts.