Hello! :)
Sorry for my late reply, as I haven't been on the site at all lately. Hehe.
Well, as for your question (if you still remember asking me lol, I'm a month late to reply :P), I'll try to explain:
Let's take the link you posted on my wall:
https://pokemondb.net/pokebase/meta/3365/pokemaster-is-doing-the-best-he-can
The number, 3365 in this case, is the id number (a unique identifier) for that particular post in the database where all of the posts on this site are stored.
So when you open that link in your browser, the browser sends a request to whatever server this site is hosted on, and that server will use whatever id number you give it (3365 in this case) to try to find a post in the database with that id, and respond with the web page that you're requesting and end up seeing in your browser. If it can't find a post with that id number, it'll just throw some sort of "404 not found" error generally. This site will just give you a red box saying "Page not found".
As you can see, the link also contains what's called a "slug", which is the hyphenated text at the end of the URL. In this case, the slug is: pokemaster-is-doing-the-best-he-can
Perhaps surprisingly, the link will still work if you omit the slug! Try it, it'll redirect you to the slugged link:
https://pokemondb.net/pokebase/meta/3365
My guess would be that the slug on this site is more for like user-friendliness, Search Engine Optimization (making it easier for people to find the site/page on search engines like Google, Bing, etc.) and perhaps for things like if you're looking through a list of links somewhere like in your browser history, it'll be easier to find that post if you're looking for it. It's possible to look up database entries using a slug too, though.
As for like why it's specifically that number, well, the id generally is just an auto-incrementing number, and usually I think it just adds +1 for each new entry into the database, but looking at the new PokeBase questions if you click on the Questions button, I'm not totally sure like about the incrementing on them. They seem somewhat random, but I'm not sure. They're incrementing, at least. :)
Well, hope that satisfies your curiosity, but if not ask away!
Merry Christmas!!!!! :)
