Ask HN: should my startup have a blog? if so which one?

getting my startup going, just wondering about the value of a blog.

obviously if we do it we'll try to make it good and keep it up to date (i.e. i realize there is no point making a blog with no posts). and i also realise that marketing the blog is a big part of it, not just making some posts, if there are any tips on marketing that would be great too!

i've also read conflicting arguments (mainly re:SEO) about doing it self hosted on a /blog vs. a tumblr blog, any thoughts?