Trending ranks projects by how many people opened them in the last 30 days, and it holds only projects that were opened at all in that window. A project nobody has opened for a month is not ranked last on Trending. It is not on Trending, and a large share of published projects are off the feed for exactly that reason at any moment.
Nothing else is read. Likes, comments, ratings, awards, how recently you published, and whether the UNI team picked the project all count for nothing here.
It counts people, not page views
Every visitor gets one record per calendar month, and that record is attached to a project once, the first time it is opened. Opening the same project again in the same month adds nothing to the count.
So refreshing your own project, or asking five people to open it twenty times each, does not move it. Twenty different people opening it once each does.
The 30 day window empties and refills each month
Each visitor record is dated from the moment it was opened, and a fresh one is created for everybody at the start of each calendar month. The pool Trending counts therefore thins out as a month goes on, and refills when the next one begins.
Two things follow. A project can slide down Trending over a few weeks without losing any real interest. And the whole feed reshuffles around the turn of the month. Neither is a fault.
The filter panel on Trending
Discipline, country, author and organization all narrow Trending. Choosing a country takes it from 4,454 projects to 417; choosing an organization takes it to 47.
Date now works here as well: the filter reads the single word the interface sends ('today', 'week', 'month', 'year') as well as a pair of dates, and Trending applies it like every other chip. That is not specific to Trending, and it applies to every sort except Relevance.
The sort menu changes the tie-break, not the field
On Trending, choosing Most Recent, Most Popular, Most Discussed or Top Rated sorts by that field first and uses the visit count only to separate ties. A-Z ignores visits altogether. In every case the projects on the page are still only those that were opened in the last 30 days, so the sort narrows nothing and widens nothing.
A project also needs a published version
Drafts, and projects whose latest version has never been published, are not eligible. Neither are private projects.
The feed is saved for five minutes
A project that has just crossed the threshold will not appear until that copy expires. See Why a project you just published is not on the feeds yet.