The search form extension is a beta offered by Google. It places a text box within your ad to act as a search on your site, whether it be for a product, brand, service location, etc. The search form extension is similar to the drop down form extension, with the main difference being that the drop down form extension gives the user a finite number of options to choose from.
I set up the search form extension for a client who sells art. I was originally going to opt for the drop down form extension for each artist the client sells art for, but I quickly realized that the number of artists was greater than the maximum allowed options for the drop down form extension (15). After contacting my Google rep and figuring out the different parameters necessary to set up the extension, he submitted it for approval. I first saw the search form extension appearing in ads two days after he submitted it for approval.
While the search form extension hasn’t made a dramatic impact on ad performance at this point, it has provided a significant lift in conversion rate. For the campaigns that the search form extension was implemented, there was a 29.8% increase in conversion rate despite a 5.9% decrease in CTR. These statistics were taken from the two weeks prior to search form extension implementation compared to two weeks after implementation.