I've noticed that about 1 in 10 blog feeds at Kindle do not share the entire entry, but just the first bit of it. Some of them give you the option to "click more", others don't, all you get is a paragraph and that's it.
I asked a techno-head blogger to explain why this happens and how to fix it, and she put together a video that explains what you need to do.
(If you don't have a Kindle and so can't check that your blog feeds probably, you can still verify that it is working by checking the settings.)
Depending on how you send you blog feed to the Kindle, check the settings - as described in the video - to make sure that "full article" rather than "summary" is selected.
(The author also offers web writing services, so check that out if you're a mind too: http://www.guerreroink.com/2010/07/26/how-to-fix-your-blog-syndication-on-kindle-video/)
Here's an explanation that a Kindle rep provided at the Kindle forums, specifically for those who use Feedburner. (It's in the video above, but since my Kindle subscribers can't watch it, you need text!) I do suggest that you go to the above website and watch the video there, if you're having problems and aren't using feedburner. She explains how to fix that, too.
1. Log into feedburner.com
2. Click on the feed title in the "Feed Title" list
3. In the page that comes up, click on "Optimize" tab
4. In the left panel, "Summary Burner" will be listed as the last option. Check if there is a tick mark beside it.
5. If so, click on summary burner option. In the right panel, there will be a "deactivate" button. Clicking on that will turn off summary only feed option.