Looks like an older thread on Mormon proxy baptism is gone, so here's another one with a new story on the practice:
Wacky.Russian Orthodox say LDS buys souls' names
Not even a year after The Church of Jesus Christ of Latter-day Saints again promised to stop baptizing dead Jews into its faith, the church has raised concerns by funding the preservation — at 10 cents a sheet — of thousands of names of dead Russian Orthodox Church members.
The church flatly rejects allegations that it is buying the names of dead souls, and insists the effort in Russia is aimed only at providing an archive of genealogical data for the good of all mankind.
Others say the church is continuing its oft-criticized ritual of posthumously baptizing the dead as Mormons — a practice that critics say is rife with ethical and moral holes.
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The Church of Jesus Christ of Latter-day Saints has long collected names from government documents and other records worldwide. The names are then used in temple ordinances, one of which involves church members being baptized by proxy to offer the dead salvation and entry to the LDS religion.
It's primarily intended to offer salvation to the ancestors of church members, but many others are included.
The practice "does not force a change of religion on any deceased person," said Dale Bills, a spokesman for the Utah-based church that has more than 11 million members worldwide. "Proxy baptism is a caring expression of faith that provides deceased persons the opportunity to accept or reject what we believe to be a blessing offered in their behalf."