To formulate Sobolev inequalities one needs to answer questions like: what is the role of dimension? What norms are appropriate to measure the integrability gains? Just to name a few… For example, in contrast to the Euclidean case, the integrability gains in Gaussian measure are logarithmic but dimension free (log Sobolev inequalities). So it is easy to understand the difficulties to derive a general theory. I will discuss some new methods to prove general Sobolev inequalities that unify the Euclidean and the Gaussian cases, as well as several important model manifolds.