I used itch.io for some years for hosting my games. Just uploaded my games, never paid much attention to the workings of their system. Lately I discovered my games could no longer be found in search of their keywords. I filed a bug, found the answers odd, suspicion grew, then asked if I had been evicted and if so why. I was not, only itch.io is a different system than I had thought.
The threads are Bug report and Asking if evicted.
So here is my analysis:
itch.io is focused entirely on competition (this was mentioned to me several times), not on digging things up efficiently.
You as developer set keywords for your game which describe it best and which should guarantee its found efficiently. Unfortunately the system may disrespect your keywords and a user may not be able to find your game at all. Your game needs to be eligible to be found by keyword search which it is only if it is popular enough. And popularity may decline over time.I cannot prove whats the meaning of popular on itch.io, its a black box. But it is safe to assume that if your game is nice but only happens to be played by few, which may even give it nice comments and good ratings, its unpopular. I assume the meaning of "popular" on itch.io is "played by many".
In my case I found my games not delivered in searches, regardless which of their respective keywords I tried. Even if the result set of the searches was very small they were omitted from search results. So my conclusion was my games were not eligible for any keyword search.
The official information I got was a bit different from my own conclusions: I was informed that itch.io has a system of so called official tags. E.g. itch.io may declare a tag as "soccer" official. When this happens only games which are deemed popular enough are delivered in searches for it. How this "popular enough" is decided I do not know. Maybe its based on number of plays/players or its manually sticked to a game based on itch.io own decision. If you happen to state that official tag as keyword for your game is of no relevance. You get overruled, meaning, if you did not get the official tag assigned you are not found. So in my case I assume all or most of my tags had become official tags. In effect my games were no longer be found in searches for their keywords.
But when a game is unpopular and does not respond to keywords, how can it be found at all ? From my experience, there are exactly two ways left for a user to dig it up: A) The user enters the exact name of the game into the search field. He must know this name a priori. B) The user enters the flow search and endlessly searches through screenshots in a flow. Or, I was informed, depending on a setting in his preferences they are delivered endlessly in chunks ("page wise"). There are categories which allow for some narrowing down, e.g. if you search for web based soccer game you could select "Web" and then "Sports". Unfortunately depending on the game category this may still result in several thousands of search results. Impractical if not impossible to dig something up.
So what are the consequences ? Give you the perhaps most extreme case, to get my point of view understood: Assume there is a user type who does not care at all whats popular, who knows what he wants, who does not like if something is pushed before his eyes and does not want anyone interfering, making up his own mind. He may even not care about comments and ratings at all but thats irrelevant for this example. So assume the user specifies his search with perfect keywords. In the system there is a perfect match for his search and he would be very happy with it. However assume the perfect match is not popular and will not be delivered to him in search of the keywords. Instead he receives popular stuff and even unrelated stuff. He may get impatient and go into cover flow and try some, not finding what he wants, then give up for now. One day he might dig up the perfect match accidentally and wonder why the hell is it so difficult to dig nice things up ?
There is a further issue I was not aware of, because of naivety: I could not find myself as creator and was informed I had searched for my display name (which is known to others) but creator search works only for username (which is unknown to others). Bummer.
Finally some advice for itch.io usage: If you select a display name, choose the username. Make the username short, one word, and extremely easy to remember. If you happen to post anywhere, even in itch.io own forums, e.g. in release announcements, always put direct links in the text to your profile page and to your game. You cannot rely on the keyword search at all. It may look all fine now but you may forget about your itch.io stuff, come back after a year, to find out you descended in popularity and your games are now practically invisible (for one not knowing their exact names a priori). And you will probably not be able to leave the depths of the abyss once pushed in.
Update 23.10.2018: I got notified that my soccer game (I left it there) can be found again from its keywords. I can confirm this. Users may have given it a rise from the dead, possibly by testing keywords or landing on the game page. Or the official "soccer" tag was just assigned.
Last update: 13.11.2018. If you think something is wrong with this analysis, notify (ed.bew@snedeneB.revilO).