That's not my experience random walker. A huge number of papers are hidden inside journals, and sites like the ACM. I run into this problem constantly.
In the last several years there's been maybe half a dozen times that I failed to find a computer science paper online. I'd estimate that less than 1% of papers in the top conferences are unavailable freely online.
As a last resort, mail to the authors.
[0] http://portal.acm.org/citation.cfm?doid=1878921.1878926 [1] http://pp.info.uni-karlsruhe.de/publication.php?id=buchwald1... [2] http://pp.info.uni-karlsruhe.de/publications.php?orderby=1...