I miss letter columns in comic books.
There's something unbelievably charming in the notion of fans of a comic book, sitting at their desks, kitchen tables, classroom desk, or what have you, and penning an honest-to-God letter to the creators of a story or character.
(More charming are the letters from small children, directly to Superman or Spider-Man. I would burst with pride to have some young fan send a letter to The Shield.)
Obviously, there are much more immediate tools available today for such interaction: message boards, blogs, Twitter, and so on, and they do have their unique charms as well.
But with the greater availability of those tools, it seems like the signal-to-noise ratio has become increasingly unfavorable. For every useful critique (or, God forbid, word of praise for the creators), there are a million posts about how any given issue "sucks."
The pen-and-paper route tended to (and I'm sure I'm romanticizing a bit here) more thoughtful and gracious commentary, which certainly made the comics fandom I grew up with considerably more welcoming than the harsher, nastier tone to the modern online comics tribes. (Again, a gross generalization; I've found pockets of online fandom I find very useful, both as a writer and as a fan.)
As a kid, I found myself actively looking forward to some of the regular letter-writers, fans who seemed to have the time and energy to write in and comment on every book on the market. My favorite? "Uncle Elvis."
"Elvis" (who apparently later changed his nom de plume to "Daddy Elvis") seemed to have a comment for every book DC published (and had a particular affection, if memory serves, for GrimJack, as well), and they were consistently thoughtful and occasionally quite whimsical.
In essence, "Elvis" invented an pre-internet avatar for himself, and used it to not only develop some minor celebrity within the fan community, but also to create a steady interaction with the people who made the stories and characters he so clearly loved.
It was a uniquely print-era thing, really, and with the subsequent rise of the web as a communication and interaction tool (and the death of the letter column in all but a few mainstream comics), it's the kind of thing that can't ever happen in quite the same way again.
I miss it, honestly.