What is the use of BizTalk server?
When we need to use BizTalk server for deploying .net application?
What are the advantages of BizTalk server?
There is none - except that BizTalk is a LOOOT more expensive, limited and
Note that this is based on you talking of a ".net application". This is like "what is the difference between a car and a truck when I need to move from point a to point b". BizTalk does a LOT of stuff which is very completely documented in the documentation (suggestion: read it). It is for business orchestration. You dont do business orchestration or can not deal with the pricing - bad choice.
Like in most product specific cases, coming heree with the obvious impression of not even having gone to the product page is not going to make people write up a copy of the product documentation here.
In your case head oover to http://www.microsoft.com/biztalk/en/us/default.aspx and read the info there.