The idea here is that publishers can save themselves the effort of building their own ebookstores while still keeping more of the money than if they listed their ebooks in the various ebookstores. They can list their titles on the site, promote them elsewhere, and then direct potential customers here to find out more and possibly buy ebooks.
I don't have full information yet, but Dimcos is promising to handle payment processing and hosting, with 100% of sales revenue going to the the publisher. This service comes at the cost of a monthly fee as well as a charge to upload each title. The company itself appears to be registered out of Finland, but this new service will be open to all.
The press release is promising that the site will include the ability to share links of the various social networks, though it's not clear how or when that feature will be enabled.
I don't know what the fees are, so it's a little hard to evaluate this service, but it is still worth a look as a possible alternative to putting your ebook in Smashwords, BookBaby, and the other self-pub services. It falls somewhere in between paying an ebookstore a commission to sell your ebooks for you anda payment processor like Gumroad.
Note that I think all the options are viable - it just depends on how much of your own time and energy you want to put into it and what you want to get out of it.