The existing Open Source Advertising program of Meta Stack Overflow is meant to invite developers to join the open source projects advertised and not to promote an open source product to end users. The exact wording below.
It must be an advertisement soliciting the participation and contribution of programmers writing actual source code. This is not intended as a general purpose ad for consumer products which just happen to be open source. It's for finding programmers who will help contribute code or other programmery things (documentation, code review, bug fixes, etc.).
But what about freeware, free open source software that target developers e.g. IDE, compilers, code quality tools, code browsing tools etc.? StackOverflow.com is the perfect site to target the developer market but free open source software (which are freeware) projects don't have the funding to run commercial advertisements.
So, why not allow such projects to have free product advertising (albeit vote based?) on StackOverflow.com as well?
I think developers would also be happy to look at ads of good developer tools targeted at them. Furthermore, such ads can be tag-based for e.g. some tools are specific to C++ only, some to Java only etc.