It is a free online encyclopedia in many languages (the english one is the most extensive).
It is very great for looking up information about things and it have information on pretty much everything (it's impressive).
If you want information on something, instead of google on it for hours then you can just look it up on Wikipedia and it tells you alot of information about it.
I showed it to my brother some week ago and we use it alot to look up interesting information such as airplanes such as F15, F22 Raptor, etc.
It pretty much contains information about everything.
All text is available under the terms of the GNU Free Documentation so you can use it freely.
Is a site where you can read free books in various subjects such as how to build a computer, how to code in C, how to cook, how to use Blender3D, how talk japanese, american history, etc.
I agree, wikipedia is great. You should also know that wikipedia may be freely edited by users worldwide to correct any information or add to it. This helps it stay completely up to date and correct. Happy searching..
I believe you can put the ones you want into a folder within the searchplugin's folder. That way when you do a new install, you can delete everything but the folder.