I love mindmaps, and I find them extremely useful. I think that a search engine for these would be extremely powerful. While not everyone will find mindmaps useful, some will, and I can see other people posting theirs on a variety of subjects too.

Would the search engine use crawlers to auto-update and grow or would it simply search your curated maps (which you or your collaborators would have to maintain and grow for as long as the project runs)? There's a world of difference between the two.

The latter. The mind maps are curated by hand and are 'human' approved similar to what various awesome lists on GitHub do.

So, TBH, having a small search engine for them is not so interesting. Drilling down to something specific should be ~ log(n) anyway, and exploring the nodes is part of the process. IMHO, search starts to be useful when nodes are one order of magnitude or two more.

I find mind maps vastly inferior to more linear representations such as outlines. Imagine if your file explorer were a mind map. Have you tried driving in a neighborhood with more curves and less grid. Grids beat mess.

I would disagree with you. For certain tasks, outlines are undeniably better such as presenting information in a file explorer.

However as far as links go, which is what these mind maps present (just a bunch of links connected with arrows), mind maps are perfect. At least for me, they have solved my 'bookmark managing' problem.

Before I saved a lot of links into safari bookmark manager only to then forget about them because it's just impossible to find it later or it takes too long. In this way, everything is sorted. I don't have to search for anything and I can just explore what I see. This is the fundamental difference between these mind maps and the search engine I am building to Google or DuckDuckGo.

In my case, the entire database that is being searched on is transparent and anyone can make a change to it. There is no black box and there is no problem of not knowing what to search or look for. You can just explore the mind map and see what you find interesting and what you don't.

This is great! I like doing the same. I collect them in trello boards. But mind maps is definitely something that gives you more insight. :)