Two citywide primary races go back to the polls tomorrow as required by city statue, because no candidate earned 40% of the vote in the initial primary. Bill de Blasio, the former District 39 Councilman, is up against Mark Green for public advocate, an office Green held before his run for mayor against Bloomberg in 2001. In the race for comptroller, John Liu is looking to carry his first-place momentum from the primary into a runoff with the better-endorsed David Yassky.
There are plenty of economists who will tell you that a rational individual will, in theory, abstain from voting, based on the simple arithmetic of cost-benefit analysis. While there are plenty of ways to explain why people vote anyway, which range from arguments about the "social benefit" of doing your civic duty to plain human herd behavior, even the cost-benefit calculus shifts significantly in NYC's primary runoffs, where voter turnout is so minuscule as to actually make your vote "count" quite a bit more than it usually does. This is particularly true given that these are very close races, victory in the Democratic primary in NYC is tantamount to winning the general election, and these two positions, while not necessarily well-reported year in and year out, are often stepping stones to higher offices and also happen to be the first and second positions in line for succession should something unfortunate befall the mayor (maybe he'll overdose on salt). In short, surprisingly few people will vote tomorrow for something that matters more than media coverage would suggest.
The duties of comptroller and public advocate are worth examining, as are the candidate websites (above) and the various endorsements, which are usually linked or posted thereon. You can also find analysis on BoroPolitics and PolitickerNY, as well as the major news outlets. I'll abstain from a full-on endorsement, though I'm happy to say I'll be voting for de Blasio and Yassky.
It takes only a few minutes: read up by clicking around, make a decision, look up your polling place (you'll be surprised how close by it is) and go vote!