Uh... well, let's see... It looks like most people are sharing the entirety of their Net history, so let's see if I can remember...
I wasn't interested in Internet communities until I was probably ten years old, although I use "communities" in reference specifically to message boards. Before that a lot of people ran GeoCities and TriPod and AOL Hometown pages, and a lot of people had their AIM usernames under the contact information. For a while I regularly talked to the guy who made the Neglected Characters comics for Super Mario Bros. HQ. I wanted to be more or less an understudy and I tried to get him to host some of my strips on the site, but eventually a friend and I made our own page on AOL Hometown called "Nintendo Rules" and hosted them there. The site doesn't exist anymore, for two very different situations. I was also a huge fan of Nintendo Land's Death Matches, and I think this is probably when I first got into writing. I scripted a few of my own Death Matches for Nintendo Rules... off the top of my head I remember Duck (from Duck Hunt) versus Pidgeotto, ReDead vs. Gibdo, Calvin & Hobbes versus Stripe the Gremlin and a Crite (from Critters... I love that movie!) and then... well, we were barely ten years old at this point and "Hehe, sex and porn is funny" and so somehow we'd gotten it into our heads that "Sextris" was an official, underrepresented Nintendo product. I've always liked bringing attention to things that aren't particularly well-known, so I wrote as one of my Death Battles "Naked Man and Naked Woman versus Male Wireframe and Female Wireframe." It was less a Death Match and more of an orgy on the Battlefield.
AOL didn't appreciate that content being hosted on their servers.
Fortunately we had backed up the site somehow (I forget if you could download backups from Hometown... maybe we just rebuilt it all from scratch), so we reuploaded everything that wasn't that particular story. Eventually it was all removed again for reasons on my friends' end of things, but I think even if that hadn't happened AOL Hometown is gone now anyway, right?
After that I briefly made some GeoCities and TriPod pages with the annoying marquee of affiliate links to other bad sprite comics and Nintendo fanpages running along the side, but I never really stuck with any of them. I couldn't even tell you the names of them now. About this same time my family got cable television, and I was introduced to the Teen Titans animated cartoon. Between that, Sonic the Hedgehog, and InuYasha, I fell down the ProBoards rabbit hole. I must have joined a dozen different forums, all under different names. At first just characters from the shows... and then which couples I shipped (Cyborg and Jinx 4 ever!!!!). I got really into forum roleplaying, and I started naming my accounts after my roleplay characters. A lot of these characters I still use in my stories, or at the very least as history in my fictional universe... Let me see... Oh, here's a chance to fit in my shitty old DeviantArt account, too!
On Teen Titans forums I started going by "Phoenix," who at first was a
Robin clone. Then there was Crow Azarath, and the third sibling: Dove. I didn't use them quite as often, but I found Crow to be a lot easier to roleplay as when I was depressed and angsty. I also invented an alien creature at this time that I liked to play as because he was fun to write... no higher functions at all, he was totally feral, so I got to basically write as an unnaturally strong predatory animal. Osselium (I don't remember how I spelled it--I just wanted it to come across as "Very SciFi"). I never used him as an account name, though.
On Sonic forums I started going by either
Reflection the Hedgehog or "Sonic the Evil." I don't remember if Sonic the Evil was a character or if I just thought it sounded cool. I do remember my dad grounding me for it because "Making a name like that is going to get you raped!"
I also apparently, looking at the stuff on my DA here, ran an Invader Zim roleplay forum... But I only vaguely remember anything from that. I still spent most of my time on AIM, and all of my significant interactions were done through there. I was a bit of a username whore, and I would just kind of hoard them as I thought up new words to start with "xx" and end with "xx." There was a mod or something later on that let me log in to different AIM accounts from the same window. That was pretty cool.
I don't know at what point exactly I stumbled upon Fanfiction.net, but I absolutely did. I always got two or three chapters into some romancey thing before dropping them. The story I worked on the longest was a Bleedman-inspired mess of a crossover starring Numbuh Four from the Kids Next Door, Bubbles from the Powerpuff Girls, Jimmy Neutron, and Kenny from South Park (who was a mutant... yeah, like the X-Men. Which is why he always wears that jacket and you can't see his face, becuase if he takes it off he unleashes a blizzard on everyone!!!). I forget exactly where that went. I remember Numbuh Four being pestered by the radio from the Brave Little Toaster, battling the bear from Over the Hedge, teaming up with Kirby (who was murdered by Fredd Krueger) and a mind-controlled Jason Voorhees where they encountered Ghost Rider, a badassified Timmy Turner, and battled Oogie Boogie and Taz (cause he's a devil, getit?) I don't remember if I ever revolved that particular plot, but they were going to eventually go up against Hades and Him and I was going to explain that Kenny was really pissing off Grim (as interpreted by Billy and Mandy) by dying all the time. (There was always this skit in my head... Kenny dies, poofs into Grim's lair. Grim smacks his forehead, says something along the lines of: "How many times do I have to tell ya? It ain't your time!" Zap Kenny back to life, turn back around to continue doing whatever he was doing only to be interrupted by one of the Happy Tree Friends sheepishly waving, smack forehead, repeat).
After Teen Titans kind of died down and I was introduced to Tales of Symphonia, I found a ToS forum where I basically "settled down" for a long time. I joined when I was eleven or twelve and I didn't lose touch with those guys until... Well, I suppose technically I could still get in touch with them if I wanted to. The forum is pretty much dead, but most of us are Facebook friends and we all check the chatbox on the bottom of the forum every now and again. It was at this forum that I invented the "Kriven" identity (at that time "Kriven" had a last name: "Guerriero"). Kriven started off, like Phoenix, as a clone of that fandom's protagonist. In this case he was basically Lloyd Irving with a blue costume instead of Red... oh and also his eyes were pitch black and his leg was made out of rocks and animated by "The Evil Demon." He swung a whimpy mace around, scored with Presea, and ruined every roleplay by having a giant grudge match with his brother Krovon (read: Sesshomaru) at the least opportune moment possible. I've basically stuck with the Kriven identity ever since.
Around that same time I joined a community called "Smash Brothers Online" which was run by some guy... JoshCube, I think? Something like that. Anyway, he threw a few giant fits. It was a shame because the site was really cool, and basically had a whole section dedicated to "I Made a Moveset for This Character" threads. A bunch of other members got fed up with that guy's stuff and we kind of forum-hopped to a few different places that don't exist anymore. I remember one of the "SBO-refugee" forums being called The Glass Owls and another being Peppermint Surge, both of which are names I use for fictional bands as an homage. On these forums I kind of gave up writing for a while to do things like play with spriting (leading me to Pixeltendo) and Game Maker and making atrocious forum sigs. I haven't improved at any of that in ten years or however long. That's okay, though.
So that's what brought me to Pixeltendo/TSR... I think I showed up either just before or in the middle of the Great Super Star Saga Sprite Style Takeover. Every day somebody new had a different idea of what Wario and Waluigi would look like in M&L. I was much more of a lurker at the time... I remember making a few posts, basically getting blown to pieces because my sprites sucked, and then posting something about... I was having a meltdown at the time, and I think I posted about being afraid that I was going to murder somebody. I don't remember the specifics. I do remember the thread being locked pretty quickly and somebody saying "Tell somebody who gives a shit." I don't remember if I participated in the community between then and 2008 (when I came back and it was TSR and Dazz was the boss).
Somehwere in the middle of all this I got involved with MUGEN stuff and made a couple of stages that I really wish I could find. Mostly hung out at Infinity Mugen Team... tried ScruffyDragon, but taht place didn't have a very friendly atmosphere. I also spent a certain amount of time on the Snafu-Comics forums, but I remember just jack shit from that. Of course I also hung out at a few other places in my Internet time.... MFGG so briefly I don't know if I even registered. I remember there being this pretty cool Sonic fan game site, but I don't remember if it had a forum. I visited that pretty regularly.
From 2008 onward I basically spend my Internet time here and Facebook... sometimes I go to the Unexplained-Mysteries forums. I've had two accounts there since 2004, and a lot of people actually liked some fiction I posted a few years back, but I'm not really active. Of course I have my poorly-maintained blogs that I wake up every morning and say: "Today I'm going to do something with them" and then don't. Lately I've been spending a fair bit of time on Reddit, because it seems like that's kind of the new place for specific fandoms to congregate, but it doesn't feel as community oriented as those old ProBoards sites used to.
TBH, I think I would probably pretty much drop off the net if my girlfriend lived closer to/with me. I mainly go online to check in with her and then I hit up TSR and derp around while we're chatting. Of course sometimes I derp when I'm procrastinating too.
As far as "Mission" I don't know if I have a "mission" in regards to my net use. I want to say "To share my fanfics/OG Fics/Reviews" but I don't post those as actively as I would need to be to feel comfortable claiming that.
Oh, that does remind me that I pretty actively wrote blog posts on ScrewAttack and made the front page fairly regularly until they changed their systems and I was like: "Fuck that shit."
There, that was probably longer than it needed to be. Oh well.
Edit: I kind of really miss the huge communities of amateur Mario fansites. Loved spending hours on the Mario Monster Compendium.