Promoting your blog in your posts, that you also link to in the signature-line of your posts (and your profile!) is considered spamming.
I.e. you can have a link in your sig-line, but then you can't refer to it further in your sig-line, or in your posts.
I'd suggest you stop before the Mods nuke you!
Actually it's the reverse. - moderator
edit to add: attempt to clarify