R, 379 caractères; 1000-379 + 170 = 791 points
Version demandant aux utilisateurs comment procéder lors de la détection d'une boucle
library(XML);w="http://en.wikipedia.org";W="/wiki/";n=1;A=c(scan(,""));while(A[n]!="Philosophy"){a=paste0(w,W,A[n]);d=sapply(strsplit(grep(W,sapply(xpathApply(xmlParse(readLines(a)),"//p/a[@href]|//ul/li/a[@href]",xmlAttrs),`[`,'href'),v=T),"/"),`[`,3);B=d[-grep(":",d)];n=n+1;if(B[1]%in%A)if(readline("Loop!2nd link?")=="n")break;A[n]=head(B[!B%in%A],1);cat(A[n],"\n")};cat(n-1)
Avec indentations et commentaires:
library(XML) #Uses package XML
w="http://en.wikipedia.org"
W="/wiki/"
n=1
A=c(scan(,"")) #Stdin + makes it a vector so we can store each iteration
while(A[n]!="Philosophy"){
    a=paste0(w,W,A[n])
    d=sapply(strsplit(grep(W,sapply( #The heart of the program
             xpathApply(xmlParse(readLines(a)),"//p/a[@href]|//ul/li/a[@href]",xmlAttrs),
             `[`,'href'),v=T),"/"),`[`,3)
    B=d[-grep(":",d)] #get rid of Templates, Files ,etc...
    n=n+1
    #Ask user if should proceed when loop encountered 
    #(any answer other than "n" is considered agreement):
    if(B[1]%in%A)if(readline("Loop!2nd link?")=="n")break
    A[n]=head(B[!B%in%A],1) #Take the first link that is not redundant
    cat(A[n],"\n")
    }
cat(n-1)
Exemple d'exécution:
> library(XML);w="http://en.wikipedia.org";W="/wiki/";n=1;A=c(scan(,""));while(A[n]!="Philosophy"){a=paste(w,W,A[n],sep="");d=sapply(strsplit(grep(W,sapply(xpathApply(xmlParse(readLines(a)),"//p/a[@href]|//ul/li/a[@href]",xmlAttrs),`[`,'href'),v=T),"/"),`[`,3);B=d[-grep(":",d)];n=n+1;if(B[1]%in%A)if(readline("Loop!2nd link?")=="n")break;A[n]=head(B[!B%in%A],1);cat(A[n],"\n")};cat(n-1)
1: Extended_ASCII
2: 
Read 1 item
Eight-bit 
Computer_architecture 
Computer_science 
Science 
Logic 
List_of_aestheticians 
Art 
Human_behavior 
Behavior 
Organism 
Biology 
Loop!2nd link?y
Mathematics 
Quantity 
Property_(philosophy) 
Modern_philosophy 
Philosophy 
16
R, 325 caractères; ??? points
Version qui, par défaut, prend le premier lien non redondant (c'est-à-dire sans boucle).
library(XML);w="http://en.wikipedia.org";W="/wiki/";n=1;A=c(scan(,""));while(A[n]!="Philosophy"){a=paste0(w,W,A[n]);d=sapply(strsplit(grep(W,sapply(xpathApply(xmlParse(readLines(a)),"//p/a[@href]|//ul/li/a[@href]",xmlAttrs),`[`,'href'),v=T),"/"),`[`,3);B=d[-grep(":",d)];n=n+1;A[n]=head(B[!B%in%A],1);cat(A[n],"\n")};cat(n-1)