Next {probably bad} Volvo's move (rumors only)

Volvo was a gag name players used when they were unhappy with Valve (which, come on, it's Valve. That's basically always.) Misspelling a name as a sign of dissatisfaction or disrespect is a common social gesture, and generally pretty meaningless in outside associations- think of it as a negative-minded nickname. As far as Volvo goes, I'm fairly sure that was used for Valve before the Diretide matter occurred.

In any case, when Valve refused to communicate with DOTA2 players over a cancelled Halloween event, instead of them behaving like normal MMO players and swallowing their dissatisfaction, a portion of the player base encouraged the rest of it to speak out, in a "If Valve won't listen to us directly, we'll make them listen (by making a big deal of it elsewhere)" manner, by flooding Volvo's social media sites.

Volvo (the actual company), in a show of unusual marketing canny, embraced the attention, playfully taking the side of the players, and thus helping defuse frustrations (and encourage warm feelings toward Volvo) by at least indicating that someone was willing to listen and speak out on behalf of the players.
Nevertheless, frustrations still remained high, as Valve still hadn't responded, so review scores plummeted, random websites were flooded with the volvo meme, etc.
Months later, when Valve finally replied, the situation pretty much instantly faded away- proving that all people really want from Valve is some degree of communication and consideration of their userbase. Not that I imagine that Valve will ever, ever be able to legitimately provide that.

The "joke" is that Volvo played along with the incident, thus cementing the Volvo connection.
Past that? Movac summed up the entirety of it, above- think of it as the same reason that someone might say "Donald Dump" or "Nobama". Misspelling names isn't meant to be taken as a joke, it's meant to be a sign that you don't take the individual seriously.