Google Search History added a new section for Google ads, in the growing list of services available in this interface, which enable you to search and manage all the sponsored links you've clicked on Google's search results pages. This might be useful if you want to buy something, but you want to check other sites before actually ordering the product: you come back to the search history and have the links there.
Google also has a search engine that only shows sponsored links. Just in case you get bored with the actual search results.
Source:→ Google system