I started a blog 6 months ago. I spent a week getting my blog publicised, it started showing up in search engine results, and all was well. 6 months later, my blog shows up nowhere, it's like it doesn't exist. What happened to my blog??These blog owners do not realise that a position in any page of the search results is not permanent.
Each page of search results, for any search query, has 10 entries. In order for your blog to show up on Page 1 of any search hit list, one entry, that was there last week, now appears on Page 2.
The owner of the blog recently demoted to Page 2 in the search hit list now has to spend some time getting his blog publicised, so his blog will appear again. Next week, a third person is going to find his blog demoted to Page 2. During all of the churn over Page 1 and 2, somebody who last month was happy to find her blog listed on Page 2, now finds it listed on Page 3. And people on Pages 3 and 4 are constantly struggling to get their blog to Page 2 and 3, respectively.
The lesson here is simple - any position in the search hit list, for any search query, is not permanent - nor will it happen immediately. Similar to the churn over Follower count, when your blog gets a better position, that's because another blog is now getting a worse position. You will get that position from hard work, more than from imaginative techniques.
Now while you are busy checking the search hit lists for the appearance of your blog, you should be checking the diagnostic tools in Google Webmaster Tools. The problem that you see, reflected in the search hit list this week, may have been visible in one or more diagnostic reports last week. You need to monitor your blog proactively, using Google Webmaster Tools, as much as reactively, using search engine results.