I tried the same thing but I can't get the Read more link to dissapear. Why?

Everything Don said in previous posts is correct, except that there is one piece of information that he might have left out.

In version 03.04.00 we opted to include the Rich Text Editor for the summary, and make sure that summary is entered when the "Make Entry Description Mandatory" option is checked. What is also not advertised or documented, is that in the case where "Make Entry Description Mandatory"  is checked, there will be NO TRUNCATION of text. This modification was done, because of the many issues people had when the blog body was used as the summary, set-up to be truncated. Basically since the body of the entry contained HTML mark-up, trucation was sometimes occurring in the middle of the HTML tags, and therefore breaking the page.

So, to recap:

• If you want to include a summary for every blog post and want to include HTML mark-up in them, then the suggested setup is to check the "Make Entry Description Mandatory". You and your users will be FORCED to enter a summary on the first (smaller) RTE. They can enter whatever and as much as they want in here, including the entire entry, but the "Read More" link WILL SHOW at the bottom of the summary - no matter what.
• If you want to show the ENTIRE entry on the first page and NOT show the "Read More" link, then enter the number "0" in the "Limit Blog Summary To:" setting (0 means DO NOT TRUNCATE, although Don's 2 million idea also works) -- Once again this set-up WILL HIDE the "Read More' link.

I hope this helps you setting it up the way you ultimately want to.

I know it hurts. It also hurts that so many things that should be in DNN are either not there, they don't work, or they require hacks to work properly.

The above hack is an example of why I complained about this module. One should not have to do all these hacks to get something to work properly. One should not have to become lucky and have someone post a hack to regain SEO functionality in the current version that was built into the previous version. The blog should reasonably allow multiple authors. If development is "slow," at least state something to the effect of, 'Updates will be released approximately every 6-9 months.' There is blog documentation but I had to watch Lee Sykes' videos to really understand the module. It is a fact that DNN module development is very uneven, with little consistency. There should be baseline requirements for timeliness of module development and frequency of reporting about module development, for example, one quarterly update and one report every two weeks, even if it is only 1 sentence long (e.g. 'Nothing new, I've been busy raising my kids.'). DNN gets a lot of publicity and then one starts working with it and finds all this module inconsistency etc. Lots of things that should be built-in aren't included, which results from DNN being almost too big for the group of people working on it, and I've seen comments on the forums that there's various politics involved (inevitable) and I'm not a programmer myself, I'm a tool user. Sorry for the rant, but I have been frustrated for so long with DNN that I really would not recommend it to anyone except if they were a programmer or have a lot of time to work through it.