When I heard that Blogsome would close down on 7 December 2011, I frantically started copying valuable blog posts to my backup blog at blog.co.uk (where I made some new blog posts as well).
Blogsome offered a possibility of exporting a Blogsome backup to WordPress. That did not work at first.
However, a few days later, I did manage to export my Blogsome backup to WordPress. Well, not all of it ... only the oldest posts, 2005-2007; as WordPress has a maximum import size, and my Blogsome blog is/was really big.
I then started to copy valuable posts manually to my new WordPress blog, dearkitty1.wordpress.com. Going forward in time from early 2008 on.
Should I make my WordPress blog, or my blog.co.uk blog, my main blog now? As far as I can see now, WordPress has some advantages, like one can embed new YouTube videos (rejected by blog.co.uk for having the iframe html tag).
I have not made a final decision on this yet. As long as my Blogsome blog still exists, as it does now, I will continue copying to my new WordPress blog.