If you want to play it in online multiplayer, then yes, vanilla Sins is pretty dead and you will need to get Entrenchment.  The game definitely needs more players online.  Sadly, most of the people who bought the game only play single player against the silly AI without realizing that they're missing out on the real game.

However, there is still lots of online multiplayer activity if you know where and when to look.  As I said, first you need Entrenchment.  Your best time for finding people and games is between 3 pm and Midnight U.S. Eastern Standard Time (aka, European and North American prime time).

Recently I have seen as many as 130 people online (which is enough for 13 5v5 games).  Now remember, all of those people won't be in the Lobby since that number also includes people who are currently playing the game.  Also, if you see a listing of games available in the Join Games window but don't see them listed, they're probably for whichever version of Sins you are not on (for Entrenchment in your case).  The online multiplayer game is great fun once you become a competitive player.  During prime time you'll find man 4v4 and 5v5 matches where captains pick the other 6 or 8 players for their team, often resulting in balanced teams and good games.  Just remember that because you are brand new to the game, you are going to get thumped online at the beginning.  Just be patient, enjoy the process of improving your game and becoming a better player while you're being beaten, watch good players in replays of the games you've played, read the Strategy forum, and eventually you too can become a good player.

Sadly, Ironclad Online doesn't receive as much attention as it needs and the Lobby channel--the default channel that you should be taken to when you join, has broken again and has not yet been fixed.  The programmers are primarily concerned with the single player aspects of the game and with producing the expansions since it doesn't make economic sense to spend 1/3 of the development and maintenance costs for a feature that, very sadly, less than 1% of all purchasers (say, 600,000+ of them) will ever use.

And, lest I forget, Welcome to the Sins Online Multiplayer community.

The stats are pretty meaningless in this game since they can be manipulated pretty easily.  These guys teamed up simply for the joy of winning an unfair fight.  BTW, this is why most of the veteran players never play FFA maps -- they almost never end up fair fights.  The last 4 player FFA I played, all 3 other players tried to kill me.

Most of the online players have moved to Entrenchment at this point.  If you like online play, get it and start looking for locked teams games in prime time.  Like everything online, some games will be disappointing, but others will be a lot of fun.

Good luck!

An online Sins game takes longer than most other online strategy games, on average -- about 1-2 hours vs 30-45 minutes.  Entrenchment only made it worse by giving additional defensive options to draw out games.  I think as a whole, Sins was a bit off target for the casual gamer to want to play it online.  Games like Starcraft and Warcraft 3 tend to get you into the action very quickly while you do a bit more planning in Sins.  Still, Sins is a pretty phenomenal game, and if you have the time and interest, competing in the multiplayer community will sharpen up your gameplay quite a bit.

What I would expect has nothing to do with the current Sins online population.

Where are the people?  I think we lost a chunk of them with ICO being flaky, the game engine crashes aka "minidumps" that took most of last year to get fixed, and the general length it takes to play a game of Sins. 

Most regular people can not afford to spend more than 2 hours playing a single game, yet we both know that a 4v4 or 5v5 occasionally goes epic.  I once had a 5 hour Entrenchment game and I have had several in the 3+ hour range.  While many games are around 1 hour in length, as soon as someone experiences a couple of these ultra long games, they may come to the conclusion that Sins multiplayer is not for them.

There are also some griefers, and while this is not unique to any game, it doesn't help with such a small community.  Sins is a wonderful game to grief in because rather than griefing people to get wins or backstab your allies, you are actually griefing to make the game take longer and make your opponent quit in exasperation.  Veteran players just suck it up and take the extra 30-60 minutes to kill someone who has dug in and is making an asshat of themselves.  Because of the length of a Sins game, you might only get in one game that night, so it sucks if someone spoils it for you.

It doesn't help that the online gameplay curve is absolutely brutal to a casual gamer.  While Sins is easy to play, there are many levels of refinement and subtle understanding of counters that a skilled player brings to the table.  When someone plays Warcraft III, for example, they get much quicker feedback when they make mistakes and a better understanding of how they are dying.  In Sins you play along happily for 30 minutes, at which point some death fleet shows up and inexorably crushes you.  Because of the small community, newcomers have to take a lot of lumps since it can be hard to find other new players to learn with.

I'm not trying to be negative, I am just like you wondering where the people are for a game that sold so many units.  The answer is they are playing with their starbases and minefields against the computer.

You tell me why you think there are so few people in the online community? 

(PS.  No one reading this get scared!  Sins Multiplayer is awesome!  Come play!)

Entrenchment actually brought people back to the game as far as I could tell.  Online populations went up, so I think this kind of panned out.

Yes, auto map distribution is a nice feature.  I don't think it was a major one to hurt online populations, but I know it means a lot more to some people than it does to myself since I prefer random maps.   Who knows.

Large/Huge single star games (4v4 or 5v5) often take LESS time then the 1v1, 2v2 or 3v3 games as once one person dies, a domino effect can occur