Internal blog with history and some SEO value versus new external blogs with specialized content?

[CondoRich]

We operate a blog inside a folder on our site and considering the launch of 4 highly focused blogs with specialized content which are now categories on the internal blog.

Wondering if there is more value in using the external new blogs or just keep growing the internal blog content. Does fact that the internal blog is buried amongst millions of pages have any impact if we want the content indexed and value given to the links from the blog content to our main site pages.

[EGOL]

Converting four categories of a blog into four outhouses will diminish your impact.

Keep those four categories on your current site and work to make then excellent.

You use two words that worry me... "growing" and "millions".    A ton of gold is worth a lot.  A ton of crap will sink a ship.

So, if your emphasis is on volume rather than quality, they you need a change of focus.