New posts now use a "Jump Break". What this means that when you are on the home page, you get a "Read More" link, instead of having the entire blog posts show up on the home page. You now just see snippets, encouraging you to click the read more link, and possibly you are more likely to comment.
On the page load side, the home page will load quicker because you are loading less data. This also improves user experience, making the user want to stay on the site more, increasing potential community interaction/user experience. This aims to increase page views (but this does not matter money wise, I do not have ads on this blog).
I know this might sound a little weird, but I am just now learning that I had this feature. I have been using Blogger since December of 2011, and have not known what the icon did.
I know...kinda odd. I'll continue to play with the jump breaks, so you get enough "grab" content, without giving no info so you don't click to see the rest of the article.
Also, if you have not noticed, the comments now have a image upload button. A few minutes ago, I also posted about HTML formatting in the comments. Make sure you catch up on these posts as well.