[zone411]

The problem with Wikipedia is that many of their articles are poorly regurgitated versions of other source articles from the Web and that these source articles get no Google credit at all, even if they are linked from the Wikipedia articles, since Wikipedia uses no-follow links. Wikipedia ranks near the top in Google for almost any term for which it has an article, regardless of its quality.

[mahmud]

Not always. Just yesterday I was knee-deep in wikipedia for linear algebra stuff and was surprised to find it more thorough than MathWorld.

[ErrantX]

That rough area of maths is one area well covered, after military and astrophyiscs I would say.