I’ve spent the past four years observing how Tumblr functions, especially how content is spread on the site, and I’ve developed a theory regarding how some posts manage to pick up more notes. This theory reflects my own experiences as someone who regularly posts original content and has slowly gained several thousand followers. I’m sure that other people have had different experiences. Tumblr is huge, after all.
Every blog on Tumblr has a “reblog coefficient,” which indicates how many notes someone’s reblog of a post will generate. If a blog has a reblog coefficient of ten, this means that at least ten of its followers will like and/or reblog any given post one of its posts.
I call the blogs with the highest reblog coefficients “anchor blogs,” as they serve as anchors for a fandom. Even when Tumblr-specific browser extensions (like XKit) are used, it can be difficult to catch everything that comes along in the rapid flow of the Tumblr feed stream, so people attached to a certain fandom will often visit one or two anchor blogs to check for new content, which they will like or reblog directly from that blog.
Tumblr has a category of older communities that we can think of as “legacy fandoms,” by which I mean fandoms that have inherited a large number of fans from fic-centric fandom communities on LiveJournal. To give a concrete example, Hannibal is a legacy fandom of Sherlock, which is itself a transitional legacy fandom of Harry Potter. In the larger legacy fandoms, it’s common for fanfic authors to have anchor blogs. Because the essentially visual nature of Tumblr as a platform can undermine the circulation of text posts even within legacy fandoms, however, sometimes fanfic writers will work together to create and co-moderate anchor blogs that are separate from their main blogs.
In many newer fandoms on Tumblr, however, the anchor blogs tend to be the blogs of popular artists. An artist’s work will generate its own fandom, which will help propel the broader fandom forward. Perhaps because they themselves are visually oriented, the artists who run anchor blogs tend to only reblog art and other image posts. In addition, there are typically several large anchor blogs within any given fandom that will reblog almost anything posted onto a certain tag or set of tags, with the caveat that they also tend to favor image posts.
What this means is that, within Tumblr-based fandom cultures, it’s rare for a text post to get more than thirty to forty notes, even if the author’s blog is fairly popular. There are exceptions, of course, but they’re generally tied to a friendship or collaboration between a writer and an artist. (Two other common exceptions are “discourse,” or aggressively inflammatory statements, and “shitposts,” which are characterized by a distinctive flavor of absurdist humor.) If an artist or other anchor blog reblogs a text post, it can get hundreds and sometimes even thousands of notes.
It’s entirely possible for someone who isn’t an artist to have what I call a “bedrock blog,” which is a blog that one or more of the anchor blogs follow and reblog from. Even if a bedrock blog only has a base reblog coefficient of ten, their practical reblog coefficient can be exponentially larger because of their association with an anchor blog. I’ve noticed a number of commonalities between bedrock blogs in my own fandoms, but one factor that stands out to me is that the people who run them tend to be extroverted and extremely active on the site.
I’ve also developed a theory that the algorithms that regulate Tumblr privilege content that has been liked or reblogged and thus vetted by certain “magnet blogs.” A “magnet blog” is one of the blogs that appears in the “recommended” section of a user’s internal dashboard if they search, track, or start using a certain tag, as the magnet blog is identified by the Tumblr algorithm as being identified with that tag. What this means is that, if you tag a post with a certain tag, and then one of the magnet blogs reblogs your post with the same tag, it’s much more likely to appear in the recommended posts (on both the website and the mobile app) of anyone who has ever liked or reblogged anything with that tag, even if the end user has never actually used the tag on their own blog before.
Based on my observations, a like or reblog from a magnet blog seems to be the difference between an image post getting 200 notes and getting 2,000 notes. This is social networking via algorithm, which means that you can never know who the “right” person to like or reblog your post is at any given time or in any given situation. If I had to guess, I might submit the hypothesis that megapopular (with 20k+ followers) anchor blogs often function as magnet blogs for the tags they use.
There are also more concrete and mechanical factors that influence the distribution of content. For example, Sunday evening from 6:00pm to 8:30pm EST/EDT is the best time to post something on Tumblr. Wednesdays and Thursdays also get a high volume of traffic, with the window between 7:00pm to 10:00pm being particularly active. The trick seems to be to try to catch the sweet spot when both the East Coast and the West Coast will see your work, and hopefully the reblogs will keep the post spreading until the people in Asia and Europe are active. Also, unlike Instagram and other social media sites, only the first five tags of any given post “count,” meaning that the post will only appear on the searches and feeds for those first five tags. There are a few other best practices concerning things such as embedded links and image formatting, but these can change according to a user’s blog theme and the site’s current policies.
When it comes to how many notes any given post on Tumblr will get, specific social connections, timing, and formatting – not to mention creativity, skill, and consistency – are important, as is having a strong social network both on and off Tumblr. That being said, there are other major contributing factors that are not random, exactly, but extremely difficult to control or predict.