You cannot post only about end-products you make/made on Main
I won't detail too much as Elemtilas already did, but it's basically off-topic. As the help-center says : "Worldbuilding Stack Exchange is a question and answer site". If there's no question to be asked, it's off-topic :).
Why we don't see questions where links to end-products are seen?
- Because the products are generally unfinished : If the work isn't done yet, people will be less inclined to display them. Perhaps if the question is about a sequel to an original product you could have it, but for the first tome of a book for instance... And if it's a sequel, then the world already has been built for the most part, right?
- Because the product is a work-in-progress and must not be leaked : In game industry for instance, it happens "fans" thrash threats at the studio/editor if "their" game is not what they wanted, maddening the mood and bringing down the sales. So com' leaks are rarely seen as ideal, to say the leash. Therefore most game developers will avoid as much as possible to show for what game they work on.
- Some people don't like over-exposing their work : They feel like it's too much advertising, have some sort of impostor syndrome (if it exists, does it exist?) or don't feel it's necessary.
- Some people ask questions out of interest, but not for making any special world. See this question here : Is it ok to ask questions that don't have specific worldbuilding use?
If you notice at the details, you'll see names that pop, names that you could look for. Some users carry the name of their world, and if you're clever, you could always look up for weird creature names and find the source. With a bit of luck, it's the same that will be used in the end product. It doesn't happen everytime but some and others also tell they're working "on a book" or "on a game". This with the question itself should give a glimpse of what you're looking for.
Also, people have favorite themes, so you can easily guess by looking at their previous questions what kind of world they're interested in or currently making, helping you focus your answers. There's one who's anatoma... automatically looking for how creatures should be made; Others are fantasy meisters, one who's looking for crazy-no things and so on. You don't need to know all the ongoing work to know what people are most interested in and know what will be best for them.
And all the above doesn't count for a good written question, which has to be enough by itself :).