It's embedded in the right sidebar below the translator and above my profile.
This replaces the Lijit search box that was available when I first set up the blog about a hundred years ago. It had become outmoded and of modest value, and frankly I had reverted to searching my own blog by typing TYWKIWDBI and the search term into Google (one of the advantages of having an odd name).
This morning the "sovrn Publisher Support Team" notified users that the Lijit search was being "laid to rest." At their suggestion I have inserted in its place a Google Custom Search, which performs a basic Google search, displaying results you can sort by relevance or date. I suppose it might sneak in some ads, but TYWKIWDBI itself will remain ad-free.
There are now over 13,000 posts on TYWKIWDBI, so I think an improved search engine should be quite useful/entertaining. Try searching something on this blog, and let me know what you think of the usefulness, capabilities, or limitations of the tool.