The answer is Yes and No.
There's no more than a limited value in any WPW post, but ocasionally the text can appear in the SERPS in response to an appropriate search query.
Other that this, though, the advantage lies in establishing -- or adding to -- your credibility, which does not have to be confined to the
SEO field.
As one for instance, I was contacted by a house buyer last year as a direct result of his having noticed my posts to WPW -- which were nothing to do with the real estate busienss but showed my involvement with it in my signature block.
It was something of a coincidence that he was also after some
SEO information, but you never do know where your prospects lie, do you?
Duncan