Complex sentence: Open threads are also used to break up the monotony of posts on the main pages of blogs-comments may build up on content oriented posts therefore authors use the open threads so page load times won't be slowed down.
Split into simpler sentences: Open threads are also used to break up the monotony of posts on the main pages of blogs. Comments may build up on content-oriented posts; therefore, authors use the open threads so page load times won't be slowed down.