Post excerpts on the Homepage?

Lately some blogs are starting to display post excerpts instead of full posts on the Homepage (e.g. Pronet Advertising). There are both advantages and disadvantages with this method.

Advantages

Displaying only post excerpts will ensure that you are not incurring any search engine penalties for duplicated content. If you display full posts on the homepage you will have the exact same content on two places, that is on the Homepage and on the single post pages (provided your archives do not display full posts, which could worsen the problem). Some SEO experts (including Michael Gray on this video) argue that this reason alone is sufficient for displaying post excerpts on the Homepage.

Apart from the SEO benefits displaying only post excerpts on the Homepage will also boost the number of page views and possibly the number of comments. Readers that before were used to reading posts on the Homepage will now need to visit single post pages (increasing the page views) and they will see the comments on every post. Should they find an interesting or provoking comment they will be much more likely to leave a response.

Drawbacks

So far so good, but displaying post excerpts on the Homepage will also have some drawbacks. Traditionally blogs were created with full posts on the front page and readers are used to this feature. A Homepage without full posts might damage the user experience for those readers since it will add an extra click before they can access the content.

The question then becomes, do the mentioned advantages out-weight the drawback coming from the user experience? Below you will find a poll to investigate the issue: