Although a certain M. D. Quack will probably disagree with me, badges are good for a wiki's community. For one thing, they show who edits the most. Although topping the Leaderboard is not the hallmark of a great user, it does show some amount of dedication. This is especially true on wikis where cheating for badges is punished. Also, it leads to more familiarity between users. Speaking from personal experience, I must say that I'm more likely to know who the big shots are if there's a Leaderboard, and am also much more likely to look at their pages.
The Leaderboard also provides reason to edit poorly. If ten one-letter edits are rewarded more than one paragraph-long rewrite/addition, why expend that much effort? Simply for improvement? Why would you take 10 minutes rewriting or adding on to a page, putting much cognitive effort into your writing, when it would be much easier to simply take those same ten minutes adding ten characters? Also, why not post nonsense categories? For example, if you simply do two-letter combinations per cat.(AA, AB, AC…ZX, ZY, ZZ), you can add 676 categories on one edit. Assuming this is your first edit, and that you do so on a "Pages That Need To Be Rewritten" page, you would earn 410 points (Welcome(10), First Edit(10), First Rewrite Edit(10) 1 Category(10), 5 Categories(10), 10 Categories(10), 25 Categories(50), 50 Categories(50), 100 Categories(50), 250 Categories(100), 500 Categories(100)). This is the bad part of the badge system: it spawns badge grabbers, some of whom are ruthless enough to pull stunts like this.
In my opinion, badges are neither good nor bad. They work on some wikis, but not on others. Here's how I would list them:
Wikis Badges Work On:
- Gaming Wikis
- Wikis That Just Want A High Edit Count
Wikis Where Badges Are Questionable:
- Entertainment Wikis
- Wikis About A General Subject (i. e. the Film Guide wiki)
Wikis Badges DON'T Work On:
- Fanfic Wikis
- Recipe Wikis (and pretty much every other wiki classified as "Lifestyle)