Do we really need more papers in STOC/FOCS?
Continuing the discussion in the STOC business meeting, I wanted to offer a somewhat opposing opinion to Lance's and Michael's view that the number of accepted papers should be significantly increased. (Since STOC and FOCS are at the moment fairly indistinguishable, the discussion below applies to both.)
In my opinion, the primary objective of a "flagship" conference such as STOC/FOCS is to highlight to researchers recent results of high quality and/or interest outside their area. We get updates on our own subfield through specialized conferences, and so the flagship conference is meant to keep the TCS community informed about progress in the entire field, and enable the transfer of ideas, techniques, problems and people across sub-fields.
An important secondary objective is to serve as a meeting place for the community, giving people in different geographic areas a chance to talk and collaborate. Why is this a secondary goal for STOC/FOCS? Because (1) opportunities to meet and collaborate can be achieved in workshops, without the tremendous effort of the refereeing process, and (2) at the moment our community has no alternative conference (or journal: I don't want to enter that debate) that performs the primary objective nearly as well as STOC/FOCS. (As an aside, people in the business meeting raised the possibility of an ICM-style meeting in TCS which sounds like a good idea to me.)
Traditionally conferences were also the primary way to make papers physically available quickly, but that has now been largely supplanted by online archives such as eccc/arxiv/eprint, and so the primary objective of refereed conferences today is indeed filtering and highlighting. But this is a very important role: without STOC/FOCS I would have only heard of papers outside my area if they were by local people, had some "buzz", or the title caught my eye- while the conference review process has its problems, it is certainly less superficial than that.
The fact that Theoretical Computer Science has grown in size and scope only makes this selection role of a flagship conference more important. Since there was no accompanying growth in our free time or attention span, I think the relevant metric is not the acceptance rate but the absolute number of papers accepted. Indeed, already STOC/FOCS together accept about 150 papers per year which is too much for anyone to follow, especially given that we need to follow specialized conferences as well.
Nevertheless, I think STOC/FOCS have on the whole been very successful, and a look at the STOC 2010 program will show some very exciting results in a variety of areas, many of which I would not have heard of otherwise. Throughout the years there were several examples of ideas and techniques transferred across areas, and rapid progress and development of other areas, that were greatly facilitated by STOC/FOCS. Program committees have always made and will always make mistakes, but the current form is still much better than having nothing at all. (E.g., I am not so naive to think my non crypto colleagues are so interested in cryptography so that even without STOC/FOCS they would go through CRYPTO/Eurocrypt/TCC proceedings to learn of the cool theory papers...)
I ignored above one more "objective" of a conference, which is to rank people in the context of hiring/promotion. The pitfalls of publication counting are well known, and here is not the place to repeat them. In any case we should not be trying to optimize our conferences for that purpose. Needless to say, accepting more papers to STOC/FOCS will not create more positions in theoretical computer science.
Are STOC/FOCS perfect? No - they could be improved in several ways. First, while the diversity of areas is perhaps unmatched by any other conference, STOC/FOCS could use better coverage in some areas (e.g., efficient cryptographic constructions, exact algorithms and hardness, and many others). Some great theory work was rejected, even multiple times, from STOC/FOCS, and some great work was never submitted. In that respect I liked a lot Dan Spielman's suggestion in the business meeting to find a way to include in STOC/FOCS great recent theory papers from other conferences. The idea of a poster session is also interesting. All talks should be videotaped and put online, so that even people who cannot make the conference (whether it's due to geography, family, or funding) can follow it. (Again, our goal should be not to maximize registration income but to maximize impact.) Personally I prefer single session rather than parallel sessions, and perhaps slightly longer talks as well, even if it means accepting a bit less papers. A pet peeve is double column papers, and page limits should be rethought now that paper proceedings seem to be on the way to extinction.
As a final note, why do I oppose adding just 10 more papers to the program? I agree this will not make much of a difference, though I think this is a change in the wrong direction. I also doubt there is any way to evaluate the effects of such a minor change. The fact that this STOC had 100 more registrants than last one demonstrates that other factors such as attractive location, strong invited talks/tutorials, and co-located conferences and workshops make much more of a difference in attendance. Perhaps SIGACT can also use some of its $800K surplus for travel support even for non student participants, and in particular people from overseas.