The key is really that an MMOG can be (and, if you know about the industry models, must be ) upgraded continuously over time.
This is actually a key best practice for success as an indie developer. Using my own development as an example, I've spent about 6 months continuously tweaking Alien Flux in order to maximise its potential over the long run. At its release, Alien Flux had a conversion rate of less than 0.1% - ie. for every 1,000 people who downloaded it, we got 1 sale. Alien Flux will remain on sale for several more years - 4 or 5 maybe - and in that time it might expect to get 100,000 downloads. At 0.1% conversion rate we'd have had a mere 100 sales in all that time, for our 6 months development effort.
By tweaking and measuring (the measuring part is critical), we've managed to deduce what makes things sell better. We now have a conversion rate of around 1%, which will in turn net us around 1,000 sales over the lifetime of the product. I admit that's pretty poor really but one of the lessons we've learned is that if you aim for a niche market you get niche sales

(We're instead going to hike the price a bit and see how that does)
There is further tweaking we'd still like to do to Alien Flux. My ultimate aim is to get it converting at around 3% - a tiny increase in percentages but a
tripling in sales.
We can take the lessons we've learned with Alien Flux and incorporate them directly into the next game, saving us months of tweaking and experimentation. The main lessons we've learned are:
1. Aim for broader appeal straight away. Defender is a niche game design in the first place.
2. The whole game buying process is targeted directly at
impulse buying. We've removed every barrier we could to just
buying the game immediately. These barriers are:
- Having to leave the application and surf somewhere
- Having to pay too much money
- Having to pay too little money ("not worth getting my credit card out for")
- Having to download the full game separately to the demo
- Being able to play the game indefinitely - why bother paying if you can still play the demo?
- Not being confronted with the opportunity to buy the game wherever possible - if your application isn't going to remind the user to buy it, who is?
The built-in online payment screens were a great success, leading directly to a doubling in conversion rate.
3. Time limit your demo. Always. But don't feature limit it if you can help it.
4. The Mac market is enormous and lucrative. The Linux market is still a total waste of time.
So what I'm saying is - writing a game and then just throwing it at download.com and waiting for the sales to roll in is a sure recipe for financial failure. Without constant tweaking and subsequent measuring of success to check that the tweaks worked, you'll get nowhere - in any game. But as you learn the repertoire of tweaks that work you can make any game sell - even a niche weirdass game like AF - and become more and more successful at it. (The trick is, uh, unlike me, not to run out of money before you start making a profit

)
Hm, big ramble - am I making sense?
Cas
