Query Expansion in Folksonomies

People share resources in folksonomies and add tags to these resources. There are often only a few tags associated with each resource, which makes the data available in folksonomies extremely sparse. Spareness in folksonomies makes searching resources difficult. Many relevant resources against a query might not be retrieved if they are not associated with the queried terms. One possible way to overcome the search problem in folksonomies is query expansion. We propose and compare different query expansion techniques for folksonomies and evaluate these methods on a large scale. We also propose an automated evaluation method for query expansion. Experimental results show that query expansion helps in improving search in folksonomies.