As modding Anno 1800 getting more popular, more people report having various issues, be it mods not working correctly, general misconceptions on how to set it up or even wanting to ajust an existing mod to their individual needs and style of play.
Without having a common hub gathering all the knowledge needed where people can go to to inform themselves players getting more and more overwhelmed and trying to seek help from other on various social platforms usually having trouble to find the specific information they need.
My goal with this project at this point will be trying to provide a comprehensive first contact point if you are not familiar with the topic yet, but want to know more about it. It should help you to decide whether you want to take this step and use mods, or if you have problems using them. It should also help you to understand mods and modders better, because you even might have some ideas modifying Anno 1800 yourself.

Modding stems from "modify" and in our case means changing the game files from Anno 1800.
Mods are single modding projects. In most cases, modding is not (actively) supported by development studios; this is also true for Anno. Modding is not supported by Ubisoft, but it is tolerated. Users are not getting banned for using mods; there is even a category for it on the official forums Ubisoft-Forum , even if there is not so much going on sadly.

Mod-users usually have a harder time with problems, because the error can also be caused by mods themselves (see Troubleshooting section).
Please keep in mind:
When you are modding your gamefiles you won't get official support from Ubisoft if you have problem with your game - act on your own risk!
If you have problems with a mod you downloaded somewhere you have to look for yourself, where the problem lies, if the modder brings an update or if you can get rid of the problem in another way or fix it yourself. Modders do not guarantee any support for their mods, but from experience they are willing to help you if you take initiative by contacting them or by reporting issues with their mods.

Well, there are some controversial opinions regarding this topic. If you would ask someone from the official support team, you would probably get the clear answer: No, just for legal reasons.
But the devs like the creativity of the modders and appreciate their engagement in the community despite Ubisofts official guidelines, so they would never act on a player utilizing mods in their game.

Even the community itself is not quite so unanimous about that. Modding is usually accepted by the users, even if ModUsers like to be sneered at. But there are also some who think that modding is basically a reprehensible act of cheating, and want the player to cleary declare if they modded their game when posting publicly. But especially since Anno 1800 there is also the other extreme with comments like "Without modding 1800 is not playable at all".

With mods you can personalize your game. You can add new buildings and create a decorative paradise; you can also make the game easier or harder for yourself (ok most people want it to make easier, never heard of a mod that made stuff harder to do up until today ^^).
Most modders have the decency to try to keep a certain balance despite their adjustments to the game. This can be a massive enrichment for the gaming experience. But even the so frowned upon "CheatMods", which consciously override the balancing seem to have a right to exist, after all there are users who want to use them.
And isn't this the most important in the end: That as many people as possible play Anno with pleasure, so that a following up titel in the series is all the more guaranteed to be made? At least I think it is.

Cheating comes from "to cheat" and means to scam, or also to trick someone.
In earlier titles of the Anno series, islands could be given certain names for cheating. Example: If you renamed your island "BonanzaCreek" in 1701, you got +100.000 coins to you credit limit. The origin of cheats are certain console commands used video game development by the programmers, so that the devs could test stuff out to be more time efficient. Over multiple different ways such cheats leaked then into the player community, spread little by little (since the existance of internet a bit faster than in previous times) and you were usualy able to find a list of them in every good gaming magazin.

In 1800, cheating for users is mostly done via mods.
So-called cheat mods (often called 'trainers') help the players to overcome certain hurdles, among other things by providing the player with money, goods or items, or making access to them much easier. Some game mechanics are even deactivated or their negative effects nullified completely.
While modding is widely accepted, cheating is usually frowned upon, even by many modders. The line where cheating starts is very slim and sometimes not clearly defined. For example, adding decoration objects is definitely not one of them; at least in my opinion. But it might be different, if you get hundreds of items into your Kontor for basically free by modding when building a single ship, just to take up a past example.

If you cheat while programming and testing game mechanics or self created mods, or while preparing a setup to make an purely informational video or stream, just to save time or to create certain situations, you would never think of calling yourself or such a person a cheater. But if you do that in a competitive setting where you try to claim an achievment or victory over others, I think we are more or less in agreement that you are 'cheating'
So whether someone is a 'bad cheater' depends on the context, because even users of cheat mods don't always use them to cheat.

Thanks to resourceful users like meow this is not difficult at all. There are just a few simple steps:

1. Download the Mod Loader (in the latest version) from github
2. Download the mods you are interested in. Sources include Nexusmods or Reddit.
   You can also combine mods from different sources.
3. Unpack the modloader folder and copy the two files in the installation location of Anno 1800 to the folder Anno 1800\Bin\Win64\
   ➔ Confirm that you really want to copy the files there when the window pops up.
4. In the Anno 1800 folder create a subfolder named "mods" (so quasi Anno 1800\mods\)
5. Extract the downloaded mods into the folder "mods" you just created.

   Consider that there are a few mod projects which put several different versions of their mod in the folder; you have to choose the one you want manually. At the end there must always be the following structure: Anno 1800\mods\MODPROJECT\data\...

   All mods in this folder that have no "-" at the beginning of the folder name will now be automatically inserted into the game when you start it.
   The other mods, which have a "-" at the beginning (example: -[Gameplay] Cargolimits) are considered deactivated and therefore not loaded.
6. Start the game, that's it :)

The first time you start the game after changing the mod folder, the start of Anno takes longer, because the mods have to be read in again.
Also, I want to point out, that with modding the system requirements can increase, so the PC could need a little more power. If you like comfort, you should look for a mod manager, which can be helpful for the collection and the deactivation/activation of mods.
Finally here is a picture to clarify how the mod folder should look like:

The selection is very diverse. Just one year after the game was released, there were already over 100 individual mods.
There are cheat mods (sometimes called trainers), sandbox modes, decoration and ornaments , everthing you can wish for. There are even new needs, buildings, etc., and the modding community is working on even more. The probably biggest part is the mod collection "Spice it up", which contains about 70 smaller mods, and the mod "New Horizons", which is planned for the beginning of 2021.
It's best to take some time to get an overview first or you can easily search for functions that are important to you. Most mods are published on Nexusmods and/or Reddit. But also the old-established communities, like the Annozone, the Maug project and surely a few others, offer choice.

Yes! But: All participating players (in case of Coop mode all 16 players) have to use exactly the same mods and the same versions.
If you have problems, just copy and send your mod folder to all other players, then it should be exactly the same ;)
In addition, faulty mods can cause problems, even if there is currently no known mod that causes problems in MP.
To avoid this you can deactivate the activated mods one by one until the game starts again without errors. After that you can switch them on one by one again and leave out the troublemaker. If it still does not work properly and no other error can be found, please send a message to the mod creator, so that the error can be investigated and fixed.

If you want to play without mods for a short time only, it is sufficient to rename the folder mods. The Mod Loader will not find any mods when starting the game, and the game will start without mods.

If you want to free your game from modding permanently, you have to delete both python35 from the mod loader and replace them with a backup of the original. But you can also make Uplay do this for you. The function can be found under Games => Anno 1800 => Properties and it is called Check files. But you will have to delete the folder "mods" yourself.

Problems with mods usually occur right at the beginning, if they either were installed incorrectly (see above), or if Anno got a recent patch update. If you encounter problems, it is best to contact the creator of the mod directly. Contact details can be found from where you downloaded the mod. Sometimes they have also pot their prefered ways of contact in a readme.txt or similar in the mod files.

If you encounter problems and don't know where they may have originated, here's a bit of general troubleshooting:
Try different saves. Even a savegame can break sometimes.
If the mod collection is new, see if mods are incompatable with each other. Some mods also need other mods as a base to function properly (usually found on the download page).
Deactivate all mods (just rename the folder "mods") and see if the problem persists. was there an update, and/or test if it also exists if you create a new game to see if it comes from Anno/Uplay itself. (Remember: Modded savegames = no support)
If the Mod Loader doesn't want to run at all, it can help to reinstall Visual C++ (make sure you have the right version), but this is rather unlikely, and Anno usually has a problem too if that is the case. You can find the download here.
More likely causes are other programms like Steam (where you have switch to offline mode) or Epic Game Launcher. In the latter case you have to uninstall the Epic client, and then install/start Anno "normally" via Uplay (no guarantee but it works most of the time).

For general knowledge, the need to exchange information, etc. some modders also have a discord server, which you can join: https://discord.gg/4XQTznE