Well, I'll start by saying that I was not into Dragonball Z 10 years ago. In fact, I had no idea it existed then. I first started watching
8 years ago, (my first sight of DBZ being the "Pikkoro-san Dai Suki!" scene

) though I wouldn't consider myself an "in-game fan" until the height of DBZ's popularity in the USA, which I suppose was whenever they aired Goku first going Super Saiyajin and first had the toys at Burger King out. Though I only watched the dub at the time, I wasn't that limited: fandom was all over the internet, and mostly I read fics, many of them "chat-speak" written, portraying Goku as a complete idiot, Vegeta as a total asshole, and Chichi and Bulma were both bitches, armed with a frying pan and rolling pin respectfully.

Many fanfics had Freeza's gender confused due to the dub, and Krillin and Gohan were kicked around a lot in battle fics.
DBZ fandom hit my area pretty hard. At school,
all of the boys were into DBZ, collected the toys, cards, folders, backpacks, t-shirts, binders, ect. and I'm sure VHS's and manga, though the anime was definately more popular than the manga at the time. A big thing was that kids would find Dragonball pictures on the internet, especially Z though sometimes GT, and would bring them to school and copy them in class - we had many great artists in class. Another big thing was saving all DBZ pictures on the internet you could find to your computer, including gifs, fanart, and midis, sometimes coming across the rare (gasp!) MPEG 2 files. ([edit] Actually, I just realized that the podcasts are all MP2s.

Wow.)
Many kids didn't know what GT was for a long time, but over the years (or maybe it was just
one year), kids went around talking about GT and AF, talking like they were experts. Dragonball Z fandom was never strong among the girls, though personally I liked it enough to watch it whenever I had the chance, and spend hours writing and reading many meaningless, OOC fanfics about it, many of them involving Sailor Moon and Pokemon. (Actually, Sailor Moon was "the girls' DBZ" in my area, and Pokemon had hit
everybody hard, though it wore off quite a bit. Everyone still has their old cards.

)
Actually, what surprises me the most about Dragonball's fandom is that it hasn't changed all that much. There are still people, though fewer in number, who are just getting into the series, writing crossover fics involving Sailor Moon and the occasional Pokemon, some of them IC, some of them OOC horribly, though "chat-fics" aren't qutie as common, with FF.net not allowing that sort of thing anymore. The only major change is the decrease in active fans.