After reaching a certain number of posts a blog has sufficient data to be linked internally rather then linking to other blogs on the net. Linking to inner posts within a blog is really good for SEO as well as to get some additional traffic because most of the links from within posts get the most exposure.
Searching your blog before searching a Search-Engine
Why not search your own blog for content to link before going to search engines?
It does give you alot of strength to refer to your own inner pages for a certain topic and it certainly does boost your serps.
Revive old content
After all old content is still content, linking to really old content which is buried down in pages!
Linking to those old posts can offer your readers with not only more info but also get those posts more exposure in search engines!
Feed readers to Site Visitors
Usually i don’t click a post in my feed reader unless i really really want to read a post, so if you are adding links within the posts to emphasize a point your readers will certainly click those links to go to the posts at your blog!
Good Link Flow
Linking to other sites is not the only way link flow is altered, the ratio at which you are linking to sites matters alot and if you more links to other sites then pages from your own that is a clear sign of paid links and/or low content value.
You could refer to our blogging tip on content for more info on this matter 
February 20th, 2008 at 9:32 pm
Hey!! Thats certainly a very nice tip. I’d never thought of it, and I wouldn’t have had I not read this today. Thanks!
August 17th, 2008 at 7:26 am
thanks for the nice tips. reviving the old content and link to them is the bast way. Also, they also need to show the related content regarding the new content they just post.