The game's servers will remain active "for the foreseeable future."
You don't get a lot of surprise hits in the world of videogames – a title is either AAA or it's not. 'Demon's Souls' was a huge exception to the rule, selling like crazy despite a small publisher, niche appeal and hardcore gameplay. Atlus announced just a bit ago that the servers for 'Demon's Souls' would be going down at the end of the month, but those plans have been cancelled.
According to the press release by Atlus, the combination of incredibly dedicated fans and "a number of developments" involving their servers means the game can stay up indefinitely. If you haven't picked up the game yet and you're wondering what all the fuss is about, you can pick it up now on Amazon for just under $20.