Have a look at this discussion :
http://stackoverflow.com/questions/593808/what-are-the-advantages-of-linq-to-sql[
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Update :
Regarding performance, Linq to SQL implements <i>Deferred Execution</i> in which the results are only loaded into the memory when requested. Hence it saves Network bandwidth and also minimizes the memory consumption.
Yes Linq to SQL does use the disconnected architecture. Yes it also supports the use of Stored Procedure which is considered as a good practice.
I hope I was able to resolve your queries. :)