janetdale on "Blogs on different websites"

I already have a wordpress account which is used with my website http://www.itseeze-shrewsbury.co.uk
If I want to write a blog for a different website, do I need to open up a second wordpress account, or can I use the one I have for both websites. If I can use the same account for both websites which have different domain names, can you please advise how to do this.