Yep, there's a rather large discussion of it over
here. Don't let the fact that it's not on Steam at the moment hold you back, though: all the payment methods Steam offers - including PayPal - are available through Plimus, and it's secure.
Bit Blot are (is?) considering their (its?) options, no doubt. The key difference with IV's position in '05 with Darwinia, and even late '06 with Defcon, was that the number of products on Steam were significantly lower, so while it's definitely a great option, there's no guaranteeing as great a response as IV had - I doubt that the number of users has grown as significantly as the number of products.