There are of course a number of hurdles for determining the life span of blogs. One of these is how do you define a dead blog? Obviously deletion is a pretty clear statement of blog death. But what about those that appear abandoned? For example, Walton's Red Star Coven has this year gone eight months without a post before popping up with something in November and (coincidentally) a statement that retirement may be imminent. So, a quiet blog can spring back into life any time. Now, as a general rule, AVPS only links to active blogs, which I've tended to define as those who've posted within the last month and a half. This seems like a good rule of thumb to determine whether a blog is active or abandoned.
But that's only one problem of measurement. The other is who to apply it to. There are hundreds of UK-based political blogs and it would be impossible to track them all down as blog rolls are updated and extinct/inactive blogs are purged - no one archives the folk they used to link to two or three years ago, and dead blogs can very quickly fade from popular blogging memory. Luckily, since the get go I've tried to plug other's blogs where I can. I also now visit new and recent entrants to blogging in regular monthly posts (which are cross-posted to Socialist Unity). This means I can work use the archive here, spread across the blogs and blogging category..
So we have a definition of a dead blog plus an archive to work from. The remaining problem is the archive mainly covers blogs from the centre left to the far left. It's very rare a Tory or a LibDem blogger receives a link from me (though it has happened). That said, I doubt very much party affiliations have an impact on one's ability to blog. Tories and liberals are probably just as likely to lose interest as lefties if they feel they're getting nowhere, or whatever.
As far as this blog is concerned, in 2006-7 55 unique blogs were named and linked to in blog posts. For 2007-8 that figure was 140 and 2008-9, 115. This gives us a grand total of 310 blogs to play with. Of this group deleted, dead and invite-only blogs account for 107 of them, or 34% (all fractions rounded to nearest whole).
It is reasonable to expect the blogs cited in my regular round ups this last year are more likely to be active than those who received a plug two or so years ago. Here are the active/inactive figures by year:
2008/9 - 87/28
2007/8 - 88/52
2006/7 - 28/27
It must be remembered that the blogs here did not necessarily start in the year in which they received a plug.
Interestingly, of this sample 84 of the active blogs cited over the course of this blog's life are three years old or older (41% of active blogs, 27% of total), and 49 are 18 - 35 months old (24% of active blogs, 15% of total). This suggests political blogging is quite stable, with 65% of the active sample taken up by 'long term' bloggers with 18 months or more activity behind them.
But what about the dead blogs themselves? Their length of operation runs the whole gamut of lifespans, from one blog that only posted the once all the way up to another that was regularly updated for over seven years. As no archive data is available for deleted or invite-only blogs, this leaves us with 77 defunct but available blogs.
As you might expect a lot of blogs (but not the majority) failed in the first six months. These account for 22 blogs overall (29%). Blogs in the 7-12 and 13-18 months categories are 13 (17%) and 8 (10%) respectively. Long-lived blogs (older than 18 months) go up to 11 (14%) in the 19-24 months category, before ranging between two and five blogs in every six monthly interval after up to 60 months (20 in total, or 26%). Beyond that there are only three blogs (4%). Here's the distribution:
1-6 months: 22
7-12 months: 13
13-18 months: 8
19-24 months: 11
25-30 months: 5
31-36 months: 3
37-42 months: 2
43-48 months: 4
49-54 months: 4
55-60 months: 2
61+ months: 3
Total blogs: 77
The median lifespan of this sample is in the 13-18 month range, and the average lifespan is 21 months. Both figures appear to confirm that blogging tends not to be a flash in the pan exercise, which dovetails nicely with the observation that most of the active blogs cited are long-term (18 months +) endeavours.
Of course, this is not an unproblematic analysis. For example, I've treated blogging life span as the time between the first post and last post. Under this rule a blog that posted for a couple of months at the start of 2008 and then maintained radio silence until firing off a couple more posts in December is counted as having been operational for all the year rather than just three months. As a significant minority of blogs fall into that category the median and average lifespan figures are distorted by them. But on the other hand, at least defining lifespan from the first post to the last is fairly neat and "precise". Considering the level of activity inbetween can muddy the waters somewhat. For example, is a blog that posts every other day during the course of the year more active than one that posted everyday for nine months and is then abandoned?
There is then the issue of sample size. 310 blogs are only a small cross section of the total number that have existed during the last three years, but on the other hand there are not millions of political blogs out there. The Total Politics blog directory lists 1,942 UK-focused political blogs (does it list inactive blogs?). I might not be au fait with statistics any more, but I'm pretty certain significance test would establish that the longevity patterns in the sample above are not random and very likely to reflect real patterns in not only the TP list, but outside of it too.
But whatever the case, more research needs to be done before a more confident answer than '21 months' can be given as the average lifespan of a blog. And that itself does not to even begin to address why regular/long-term bloggers decide to give up.