It can be a plugin, service, host.. anything. I'll go first, for me, investing in CDN is probably one of the best thing that I've ever done to help my blog flourish. I don't know if it increased my rankings but I am pretty sure that it increased my overall visitor's average time on site, pageviews per visit and lowered my bounce rate. Which in turn increased my overall income every month. I advise everyone to get a CDN, don't be like me, I waited until I was getting 150k UV's per month before I got one. Imagine all the potential visitors who exited your site because of the ghastly speed performance of your blog. I also bought http://codecanyon.net/item/visual-composer-for-wordpress/242431 and I'm loving it, I'm not great with design (I suck at color coordination since I'm color blind) so having an on-the-fly visual composer like this really speeds up my work, especially since I'm always tweaking my site. Share yours?