In practice there is a certain kind of minhashing that is used in key-value stores, which is called a Bloom-filter.

Basically it is a probabilistic bitmap index for quickly telling if a certain elem is in a set. It is used in BigTable, Hbase etc.

http://en.wikipedia.org/wiki/Bloom_filter

The Jaccard similarity (or Jaccard index) mentioned in the article is used for finding similar items in a big set. E.g. Google News uses it for aggregating articles on the same subject.