Why not merge reputation across SO, SF, and SU?
Edit-2: If you want, I am fine narrowing my topic to tex.stackexchange,com and SO. TeX is a programming language, differentiated from the main SO site, I imagine for neatness, or compactness. I contest that there is a large difference between (C# and Fortran) and (Java and LaTeX).
Programmers often find themselves working in several languages, some people program in C++ and Java. It just so happens that one of mine is LaTeX (including some very programmatic things like PerlTeX and TikZ/Pgf). I keep seeing that LaTeX questions should be moved and/or are closed on SO for being off topic. I just wish that I didn't have to work towards two different sets of reputation goals, one for each site.
Therefore, just like we can link profiles between sites, I ask that we be able to link reputation across sites.
Now I understand, somewhat, why a person with reputation at SO possibly shouldn't have it at http://cooking.stackexchange.com/ , for the reason that they may not be proficient at it, and rep says to other users that you are knowledgeable in the field. However a counter argument from the perspective of the community maintenance of the sites, a person with reputation has proven that they are responsible in their use of the site. So perhaps even cooking and SO could share.
Edit: ok, as per the link in the comment, if we don't want to link the rep points, for the reason of appearing an expert, what about linking the privileges, since that is really where the community trust is shown. This is at least something of what I am after.