In LDS culture marriage is a vital aspect of life and the afterlife. As such, dating can become just as important of an aspect of life since most most marriages are formed through dating relationships. However, the unique moral values of members of the Church of Jesus Christ of Latter-day Saints can make finding a suitable partner with those same values a little more difficult. Also, many communities have very few members of the LDS faith within them. Because of this, LDS dating sites have become much more popular.
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eHow Article: About LDS Online Dating Services