Hence the magazines behind the counter? 
My wife and family tell me I’m a know-it-all, so I guess anything’s fair game. The topics I tend to post on most frequently are:
[ul]
[li] Baseball (I have a particular interest in minor league baseball, and in sabermetrics).[/li][li] Music, specifically bass and guitar playing, as well as blues, rock up to about 1988 (especially garage band, power pop, punk, new wave, and “alternative”).[/li][li] Judaism, and in particular conversion to Judaism (being a convert myself)[/li][li] Software and the software business. I’m not a programmer myself, with occasional exceptions, but I’ve done nearly every other software business job (tech support, QA, product management, implementation consulting, marketing and sales) at nearly every level (entry level up through VP).[/li][li] The publishing and advertising businesses. I’ve been a proofreader, copyeditor, and technology program manager in publishing, and a proofreader, production assistant, traffic manager, and copywriter in an advertising agency – though my agency experience was fifteen years ago. I still have close friends in fairly advanced positions at book publishers, so I try to keep up with what’s going on.[/li][li] Graphic arts in general, and specifically graphic arts technology and typography. At one time, I probably knew nearly as much about use of the PostScript programming language for printer control (as opposed to using it for page description) as anyone around who didn’t actually work for a printer company (or who isn’t named Frank Braswell), and was quite intimate with the gory details of the Adobe Document Structuring Conventions, the format and use of PostScript Printer Description (PPD) files, the Open Prepress Interface (OPI) specification, the theory and design of print server/print spooler software, etc. I’ve also been a devotee of the lettering arts since I was a teenager – taught myself calligraphy as a teen, read and learned a lot about type through the next several years, worked as a proofreader and typesetter after graduating from college.[/li][li] Macintosh computers in general, and in particular cross-platform interoperability issues (networking, file formats, etc.). For years, my bread-and-butter was cross-platform networking products.[/li][li] Bad/obscure movies – haven’t kept up to date on this one, but I’m pretty deeply conversant with the careers and oeuvres of Ed Wood, Ray Dennis Steckler, et al.; I co-taught an adult education night course at a local university in bad movies many years ago (1988 or so).[/li][li] Literature. My undergraduate degree was in English, and I came to Atlanta to enter the Ph.D. program in English lit at Emory. I still have opinons on a wide range of literary topics.[/li][li] Information theory. Reading Pynchon started me off down this path, and it’s remained an abiding interest ever since.[/li][li] Evolutionary biology and evolutionary psychology. My information theory interest led into this, and it’s probably been my primary extracurricular interest for the last fifteen years or so. I’ve read as widely as possible in these fields, though not as deeply as I’d have liked.[/li][li] Cognitive sciences. Everything from neuroscience to user interface design. Anything related to how our brains develop and function, and how they got that way. as well as why they’re good at doing certain things and not so good at others. Also ties in with an interest in design, particularly user interface design and “design of everyday objects” (to steal from Donald Norman). [/li][li] Arkansas. As my user name implies, I’m a native of the Natural State (aka the Bear State, the Diamond State, the Wonder State, etc.) with an continuing interest in the state and its history, even if I’ve been away for nearly twenty years now.[/li][li] Travel and related topics. While I don’t travel as much as a lot of people I know, I rarely go more than ten or fifteen days without getting on a plane these days.[/li][li] Kids and parenting. Everyone’s got an opinion on topics about kids, whether they have any of their own or not. I now have three, age 7, 4, and 5 months. All were c-sections, two emergency and one scheduled, so I know a bit about that (though not as much as my wife). All of our kids have been breastfed, and my wife’s a card-carrying La Leche League member, so I’m fairly well-informed on topics related to that. [/li][/ul]
Then there’s the stuff I know something about, that no one ever asks about:
[ul]
[li] Disc golf; haven’t played much the last several years, but used to play regularly (and once played a tournament round with Ed Headrick, who invented the lines on top side of a Frisbee® and the game of disc golf itself).[/li][li] AppleTalk networking. Not even Apple uses AppleTalk anymore, but it was my primary daily concern for several years.[/li] The literary career of Albert Pike. Most people who know of Pike at all know him as perhaps the foremost American Mason of all time, who produced volume upon volume of Masonic material. Or as a politician/newspaperman of Arkansas’ frontier days. Or as perhaps the only person to be accused of treason by both the Federal and Confederate sides during the Civil War, much less to be exonerated by both. In his younger days, however, he fancied himself a poet, and produced a series of “Hymns to the Gods” that borrowed heavily from Lempriere’s Classical Dictionary and from Keats, and that nevertheless received positive critical notice from and publication in Blackwood’s Edinburgh Magazine in the 1830s. Pike republished these poems in edited form in a privately printed collection entitled Nugae, along with the rest of his poetical efforts from the intervening years, in about 1854. As a first-year grad student, in my Textual Criticism class, I created a variorum edition of Pike’s poems. I’ve probably spent more time reading Pike’s poems than anyone other than the man himself; certainly than anyone in the last 150 years.[/ul]
Left out cooking and food science from the topics I post on frequently.
I’d consider myself an expert in grammar and spelling (and AP style 
).
I know a lot about rock/pop music, especially indie stuff. My specialty is Scottish pop. I’m also pretty knowledgeable concerning Talking Heads.
In regards to TV: The Kids in the Hall, The Simpsons, Schoolhouse Rock, commercials.
I don’t claim to be an expert on anything. I do have 16 years of military experience, active and part-time, enlisted and officer. I also have 6 years of law enforcement experience. I sometimes chime in on related topics but I hang mostly in CS.
On the flip-side I am a horrible speller so forgive me when I make a mistake.