Define conversion optimizer with the context of AdWords.

Conversion optimizer, also known as the Target CPA building, is a tool that is used for manipulating bids which decide as to which clicks on the ad can add more worth to it. Conversion optimizer usually helps in getting a better return on investment. If the advertiser or marketer sets a relatively low target CPC (Cost per conversion) for any campaign, conversion optimizer works in placing conservative bids only on those particular keywords that Google estimates to be sure in terms of their probability to convert them for the marketers. It will result in relatively cheaper conversions.

While on the other hand, marketers who specify a relatively higher CPC, the conversion optimizer may have the ability to bid more aggressively and can compete for a higher ad position with a broad range of keywords.