I have found a good way of recording ideas that are not yet ready for publication. These are likely to form the basis of articles or blog entries that I publish in the future, but are generally things that need a bit of research and polishing up first.
There are a couple of plug-ins for Drupal that assist in managing drafts, but if your needs are simpler then there is an easier way to manage draft content. You can store draft posts without any third-party help. Simply uncheck the box for Published in the Publishing Options before you save and the item will effectively be draft. This is probably obvious to experienced Drupal administrators, but it wasn’t to me when I first started using it.
In this site, I have created a view that lists all the unpublished articles. I’ve put a link to this at the top level of the Navigation menu, although it’s only accessible to administrators. So I can quickly bring up this list, click on the link to an article I wish to change and then edit it. I can then save it again still as a draft, or I can publish it if it’s ready.