We have had many debates about standards in the Web Design forum over the last few weeks and this, again, is I'd suggest a fault in the standards. The de facto way of opening a new window in HTML is to use target="_blank". Personally I think the standards are splitting heirs over HTML "strict" (WTF that is I don't know) and I'd like to see how the "standards" suggest you open a new window in HTML.

As for registration - I click on one of your links, saw you had to register and closed your site. Just one users experience.