Linden Lab are currently working on the transition from the old to the new SL community platform, as previously announced last week. The SL Blogs, SL Forums and SL Answers are currently only readable at the moment until 2nd, March 2011, when the new SL platform launches.
Many are reporting that when you visit the SL blogs it pops up with a security certificate warning. Chrome and other browsers show the same security certificate warnings and heres the image of the warning below.
The lab are currently working on this and it should be resolved soon.