Tyler Cowen is an economist who maintains a blog at Marginal Revolution. Every day he shares a collection of links with his readers, and he has done so since 2008. You can read some potential reasons for why he does this in Assorted Links I.

Because Cowen has been sharing links for so long, it seems reasonable to ask if we can discover changes in his content consumption through changes in the frequency with which certain websites are linked to.

Scraping link data through to December 31st, 2023, the most common websites fall into three categories — mainstream news and media, such as The New York Times, the BBC, The New Yorker, and The Economist; blogging platforms, such as Medium and Substack; and micro-blogging platforms, which really only comprises X/Twitter.

The relative frequencies over time of these three categories is shown in the chart above, with the ten most commonly linked mainstream news and media websites grouped as ‘MSM’, and blogging disaggregated by the main platforms.

It’s easy to spot the steady decline of blogging as a whole from 2009 to 2013. From 2013 the original platforms die away, Medium comes and goes, and eventually everything ends up on Substack; but the proportion of Cowen’s attention directed towards blogs over the last ten years seems to remain mostly unchanged.

During this same period, linking to Twitter grew significantly, and linking to mainstream news sources declined. It’s not clear if Musk’s acquisition has had an impact, with growth in shared Twitter content continuing after the deal closed, and the first large drop in years occurring in the second half of 2023.

To chart links over time to a wider range of destinations, URLs were processed to extract domain names below the top-level domain, together with any subdomains. Each instance of a link to a popular domain or subdomain is shown below. For example, a link to dynomight.substack.com would give rise to a mark on both the row for ‘dynomight’ and the row for ‘substack’. In any clear-cut cases where the domain of a website changed over the period shown, such as guardian.co.uk moving to theguardian.co.uk, the entries have been merged. There are however instances where an author moving around isn’t captured, for example Matt Yglesias moving his writing from ylgesias.thinkprogress.org to www.slate.com shows up as a sudden break in the row for ‘yglesias’. The most popular Twitter accounts are also included, and the subdomain of the page you’re currently on was thrown in for good measure.

Outside of the most popular link destinations, such as mainstream news sources and Twitter, websites seem to fall in and out of favour. In some cases it’s easy to recognise this as a consequence of certain world events, such as links to Medrxiv and Biorxiv suddenly increasing with the onset of the Covid-19 pandemic, and decreasing as it began to pass. But it also seems to be a general pattern, where a new content source gets an initial burst of attention, and then fades away again. Given the fairly specialised nature of most blogs linked to (e.g. constructionphysics.substack.com), maybe this isn’t so surprising when the individual curating the links is one very aware of the concept of diminishing returns.

In addition to URL data, a links post also comes with descriptions by Cowen of each link. These descriptions often invoke certain long-running themes, for example ‘those new service sector jobs’ as the link text for an NYT piece about therapists treating climate change anxiety.

The final chart below shorts the relative rankings of the most common themes each year. Themes that went unmentioned in a given year appear below the dotted line. ‘Markets in everything’ is consistently the top performer, Straussianism peaked in 2021, ‘There is no great stagnation’ has been stagnating recently, and ‘Average is over’ is over.