Well, my life would've probably been rather different.
Before I discovered AH.com, I primarily frequented anime-related forums. My membership here helped me branch out and "de-anime" my interests a bit, while also expanding my interest in history and honing my political opinions. While I had an interest in timelines, without a venue to post my ideas I probably would've never written A Revised History of the Future - and, as a result, I'd still have unrealistic concepts about technological advancment and cultural change (just take a look at my first AH.com TL to see how far I've come). Without AH.com I wouldn't have discovered the Worldwar series as early as I did, which butterflies away my Race ISOT story (I discovered the ISOT concept here). While the ideas behind The Bird Men of Patagonia were generated before and separately from AH.com, without the site they might've gone in a VERY different direction and, without this site as motivation, I probably would've never written it.
So, I'd be less of a writer and generally poorer intellectually, overall. I probably would've found another website to hang out at, but who knows where my personality would've gone over the last six years without AH.com (probably would've turned into much more of an anime nerd).
Outside me? No CF.net and no HA.com, for a couple.