I read this on Chris Pirillo's RSS resource site. Clipped from this post, it makes a point that I agree with: summaries don't entice me to regularly read the content from that site.

If I read a summary, I have the extra step of opening the site in a browser and reading the article there, complete with ads and graphics. Two sites, TidBITS and MacInTouch do this to a frustrating end. The summaries are either inconsistently used, in the case of TidBITS or vague and of no value, in the case of MacInTouch. I still read both publications regularly, just as I did before they had an RSS feed because the content is so good. It's written and edited well and their journalistic reputation is of the highest quality.