On wikis, people are free to collaborate but sometimes edits can be unnecessary to say the least. However, while the person may have done an unnecessary edit, that does not exactly mean they did a bad thing. Here are examples of criteria for what makes an edit just an unnecessary edit and what makes one actual vandalism/spam.

Good Faith Edits that are Wrong

  • A small removal of something that they may think is unnecessary but actually is. Removing necessary information is not necessarily vandalism. Vandalism is when it's done deliberately to be a jerk.
  • A misunderstood undo can also count as one. Even I recently made one but please don't take that as me acting in bad faith especially considering I undid the edit. Undoing an edit can be a mistake in some cases or just a disagreement that may be wrong depending on the point of view.
  • Adding unnecessary details is also one. For example, if someone were to write "Homer Simpson is yellow" on Homer Simpson's article on The Simpsons Wiki, that's not a spam edit. That's just unnecessary. "Homer Simpson is good at being the safety inspector of the nuclear power plant" may be considered that as we all know (even if you don't watch The Simpsons) that Homer is quite lazy and incompetent for comic relief.
  • Breaking the fourth wall. When a wiki breaks the fourth wall, it is when they acknowledge their existence on articles. While it is generally discouraged on most wikis, it's not necessarily a spam edit. The Plants vs. Zombies Wiki used to have badges on articles until we decided to remove that. Some also do have reason to break the fourth wall like Encyclopedia SpongeBobia has an article about themselves but not about the social aspects and structure of the wiki but mostly just presented as a fansite.
  • Grammar. Poor grammar may be annoying but it is definitely not a bad faith edit unless it just happens to be in one. However, some edits involve changing American English to British English when it should be the other way round or vice versa. These are not bad faith edits as they are technically correct but not in the right place. For this reason, a Manual of Style is recommended for a wiki.

"Actual Bad" Edits

  • Removal of all content from a page or replacing it with something obviously incorrect. Other things that can be done are insulting messages, political statements, a bit of profanity (even if your wiki does allow swearing) and spam images like extreme gore and porn, which can violate the ToU.
  • Deliberately ignoring the advice and good faith you assumed after you undid the edit can in some cases be considered a "bad faith edit". However, it really depends. While edit wars are bad, both sides might just be arguing about what they believe to be right.
  • Adding stupid, pointless, annoying things (SPAT). Well, it's really SPAM but meh. By that I mean things like obvious gibberish like "sssssss" or something like that. (I lost some of my dignity doing that as an example just now.)

For methods of how to assume good faith and how to act in those cases, there is a help page on Community Central to tell you how.