If you want to implement expandable post summary for your blog, the instructions are given in these 2 posts:
Expandable post summary for New Blogger
Testing phydeaux3 peekaboo expandable post summary
Someone asked about whether search engine will crawl the whole post if one used the expandable post summary to only display part of the message, with a "Read More" link to read the whole post. Panther of Beta Blogger for Dummies gave a link to a site Spider View where you can type in the URL of a site and view how a search engine sees that site. Expandable post summary has been implemented for this blog Good Health Information so I decided to test it out.
Currently, the latest post in Good Health Information is Relieving Depression from the Inside and the summary displayed in the home or index page is:
with a "Read More" link below that. (If you go to Good Health Information weeks after today, that post will probably not be in the main page anymore, but you can read the full post at Relieving Depression from the inside and you can compare with what is displayed by Spider View when I typed in the URL http://good-health-information.blogspot.com which I put in the scrollbox below:
To make things even clearer, I will do a screenshot of what is displayed by Spider View with the post summary of that post highlighted in blue (click to enlarge):
Conclusion: Search engine spiders does read the full post even if you use the expandable post summary,