Of course postmodern philosophy is based on bourgeois idealism, but like any bourgeois theory or science, there could be something of use to Marxists in it. How do we sort the wheat from the chaff in postmodern philosophy, take the useful observations, and explain them in terms of dialectical materialism? Who are the postmodern philosophers who have theories that can be of use to Marxism? Which theories, and why?
Personally I've downloaded some of Baudrillard's works recently after reading a summary of his theory of simulacrum. It basically seems to be an argument that the process of accumulation of image and memes is analogous to the process of accumulation of capital that Marx describes in Capital V.1:
"If a capital of £1,000 beget yearly a surplus-value of £200, and if this surplus-value be consumed every year, it is clear that at the end of 5 years the surplus-value consumed will amount to 5 × £200 or the £1,000 originally advanced. If only a part, say one half, were consumed, the same result would follow at the end of 10 years, since 10 × £100= £1,000. General Rule: The value of the capital advanced divided by the surplus-value annually consumed, gives the number of years, or reproduction periods, at the expiration of which the capital originally advanced has been consumed by the capitalist and has disappeared. The capitalist thinks, that he is consuming the produce of the unpaid labour of others, i.e., the surplus-value, and is keeping intact his original capital; but what he thinks cannot alter facts. After the lapse of a certain number of years, the capital value he then possesses is equal to the sum total of the surplus-value appropriated by him during those years, and the total value he has consumed is equal to that of his original capital. It is true, he has in hand a capital whose amount has not changed, and of which a part, viz., the buildings, machinery, &c., were already there when the work of his business began. But what we have to do with here, is not the material elements, but the value, of that capital. When a person gets through all his property, by taking upon himself debts equal to the value of that property, it is clear that his property represents nothing but the sum total of his debts. And so it is with the capitalist; when he has consumed the equivalent of his original capital, the value of his present capital represents nothing but the total amount of the surplus-value appropriated by him without payment. Not a single atom of the value of his old capital continues to exist. "
marxists.org
I don't know whether or not Baudrillard makes the comparison in S&S, but he was an (idealist, critical) reader of Marx so he could also have ripped it off without giving credit. Either way, it rings true and hints to me possible inroads for Marxist analysis of mass culture.