1. A computer-implemented method for ranking documents with social tags, the method comprising: receiving a number ranking feature containing a number of times a document was tagged; receiving a textual property ranking feature containing a union of each social tag associated with the document; transforming the number ranking feature into a static input value; transforming the textual property ranking feature into a dynamic input value; and determining a document rank for the document by inputting at least one of the static input value or the dynamic input value into a ranking function.