The contents of all pages are searched to find links to the current page. The BackLinks function also answers the question: "Which pages contain the title of this page?".

Notice: "unserialize() [<a href='function.unserialize'>function.unserialize</a>]: Error at offset 1016 of 1030 bytes" (...repeated 3 times)

Warning: "array_merge() [<a href='function.array-merge'>function.array-merge</a>]: Argument #2 is not an array"