I managed few blogs. Some good ones, some crappy ones. I just notice that on this my one blog, each time i publish an article, just a second after that, i checked and its already got indexed by google (google only, not yahoo nor bing) Question is what makes a blog loved by google so much that it got indexed so fast, while the other took more that 1 hour to get indexed?
google bots are just too advance that they can crawl and index fresh contents.. and your blog might be link to a site that crawl by google regularly..
This goes the same for blogger and wordpress, Google certainly loves blogs. Even pinging is not needed anymore because it is autmatic. Page rank though is still not automatic and should be work on just like any other sites.
It actually depends on how often you update your new blog articles. Also remember if your site is below 3-4 months old, then it is obviously that your new article gets indexed very fast. BTW that is a great achievement in terms of SEO, which means you are doing your work perfect Have fun !!!