sanity testing is seeing if the application is fit enogh 
for actual testing. eg: testing the weblink,browser etc.
smoke testing is testing the major functionalities in the 
entire application. otherwords..,checking here and there 
and get a feel of the whole system regarding the 
functionality.
 

smoke testing is conducted to ensure that application is 
stable or not 4 further testing.

Sanity test is used to validate all major functionalities

Both have stated two different views so pls some on infrom 
the correct answer

Smoke
 Sanity
 

1
 Smoke testing originated in the hardware testing practice 
of turning on a new piece of hardware for the first time 
and considering it a success if it does not catch fire and 
smoke.  In software industry, smoke testing is a shallow 
and wide approach whereby all areas of the application 
without getting into too deep, is tested. 
 A sanity test is a narrow regression test that focuses on 
one or a few areas of functionality. Sanity testing is 
usually narrow and deep.
 
2
 A smoke test is scripted--either using a written set of 
tests or an automated test
 A sanity test is usually unscripted.
 
3
 A Smoke test is designed to touch every part of the 
application in a cursory way. It's is shallow and wide.
 A Sanity test is used to determine a small section of the 
application is still working after a minor change.
 
4
 Smoke testing will be conducted to ensure whether the most 
crucial functions of a program work, but not bothering with 
finer details. (Such as build verification). 
 Sanity testing is a cursory testing; it is performed 
whenever a cursory testing is sufficient to prove the 
application is functioning according to specifications. 
This level of testing is a subset of regression testing.
 
5
 Smoke testing is normal health check up to a build of an 
application before taking it to testing in depth.

 
 sanity testing is to verify whether requirements are met 
or not, 

checking all features breadth-first.

Sanity testing :This is a type of initial testing performing
on application and make sure that it has no blockages.
Blockages in the sense whether the all functionalities are
avialable or not in order to perform detailed testing on the
application.

Smoke Testing:This is also a type of initial testing
performing on application in order to test whether it is
stable or not.

But companies are following either one.

Smoke testing is conducted to ensure whether the most 
crucial functions of a program are working, but not 
bothering with finer details. (Such as build verification).

Sanity testing is a cursory testing, it is performed 
whenever a cursory testing is sufficient to prove the 
application is functioning according to specifications. 
This level of testing is a subset of regression testing

Sanity: Initial Testing is conducted to ensure that every 
link is working correctly or not, to proceed for testing.

Smoke: when the build is tested, the total is build is 
tested again overall to ensure every thing is working 
correct.

****Some companies say both are same*****