The Ultimate Google CSS Guide

What is Google CSS?

CSS stands for Comparison Shopping Services – price comparison services – and affects the search results on the Google homepage.

Price comparison portals (CSS) can submit bids in order to place Shopping ads for retailers they represent on Google search results pages. Google Shopping bids on behalf of the merchants it represents in the same way as any other price comparison website.

This means that you as a retailer can use the Shopping ads on the Google search results page in different ways: you can submit your product data to any price comparison portal, including Google Shopping. You can also use several price comparison portals at the same time.

Originally, Google used the search results page exclusively for its own price comparison, Google Shopping. Other price comparisons appeared much later in the search results. The European Commission recognised unfair competition because Google exploited its monopoly-like market position to give preference to its own offer.

In order to create equal opportunities, Google opened the advertising platform under the name Google Shopping Europe (GSE) as a price comparison and opened it to external price comparison sites – the so-called Google CSS partners. As a result, all Shopping ads that appear in Google's main search results are part of a Comparison Shopping Service (CSS).

Google Shopping itself also functions as a CSS ("From Google"), takes part in the bidding auction like the other price comparison platforms and competes with other CSSs that submit bids on behalf of retailers.

In order to use its own price comparison in conformity with the EU, Google's own price comparison keeps around 20 % of the bid of a retailer who uses Google's own price comparison as a margin. Only in this way can Google Shopping Europe pass as an independent price comparison, which accordingly also has to work in a profit-oriented manner.

However, this reduces the bids of all advertisers who use Google Shopping Europe by around 20 %. If you use a CSS partner for your ads, the margin for Google Shopping Europe is completely eliminated.

For Google users, the difference is hardly noticeable – the only visible change is the added line "From …" at the bottom of the ad.

What changes with the use of CSS Shopping?

For you as an advertiser, the composition of your Google Shopping bids – with which you enter the auction for the ad rank – will change in particular:

Let's say you start with a CPC bid of € 1. If you are still using Google Shopping Europe, € 0.20 will be deducted from this. The result: for ad rank, you bid with a reduced bid of € 0.80.

If you do not advertise your products via GSE, but via another Google CSS partner, this margin no longer applies. The bids are entered in the auction in full – € 1.

Your advantage: you win significantly more auctions with the same CPC bid and can significantly increase your traffic and sales.

Is it worth switching to a Google CSS partner?

Everyone who runs Google Shopping Ads should switch to Google Shopping CSS with the help of a CSS partner. The effort is minimal, the benefits are enormous.

In most industries, so many online retailers now use CSS that you are no longer competitive as a shop if you don't use a CSS partner and go into the auctions with correspondingly lower bids.

Advertisers pay up to 20 % more per click if they place a Shopping ad via GSE instead of via a CSS partner. In practice, CSS operators also charge for their services – usually a fixed monthly fee, sometimes a percentage of media spend.

Compared to the margin charged by GSE, the costs for external CSS use are lower in most cases. For advertisers with a small budget it is important to check carefully whether working with a CSS partner is worthwhile, or whether fixed fees may offset the savings.

Strategies & best practices for the optimal use of CSS

If you have decided to switch to a Google CSS partner, the question arises about the optimal account and campaign setup: should you move all accounts to a Google CSS partner, or are there even advantages in splitting accounts between GSE and CSS?

Variant 1 – the double strategy: you use Google CSS and Google Shopping Europe in parallel and serve traffic with different bids depending on placement (Google main search vs. Google Shopping tab and partner networks). High bids on the main page through a CSS account, low bids on the Shopping tab and partner networks through a GSE account. This is particularly relevant for very large advertisers who do not shy away from the additional effort.

Variant 2 – complete move to CSS: in practice the double strategy rarely produces measurable added value while the maintenance effort is considerably greater. We therefore recommend the complete move with all accounts and Google Shopping campaigns to CSS. Very little effort with full utilisation of all CSS advantages.

The integration: full switch vs. association

In order to display Google Shopping ads via a CSS partner, there are two options for converting an existing Google Shopping Europe account to CSS: full switch or association.

With a full switch, the advertiser's Merchant Center Account (MCA) is fully integrated into the CSS partner's Multi Client Merchant Center (MCC). There are some technical aspects to consider when making this move. If not the entire MCA but only a sub-account is moved, access rights can be lost during the move.

The main advantage of the full switch is that the CSS partner has access to the product data and can identify and fix problems directly. However, the advertiser's dependency on the CSS partner is higher than with the association model and requires trust between both parties.

If an advertiser chooses the association model, their MCA is linked to the CSS partner relatively easily. The advertiser's setup can remain unchanged, the migration effort is very low – an email from the CSS partner to Google is enough to request the changeover. If only one sub-account of an MCA is converted, the same risks of losing access rights apply as with a full switch.

The advantages of the full switch (full access to and insight into the product data by the CSS partner) do not apply directly here. The CSS partner can, however, be given access to the customer account or data feed via user invitations.

Full switch and association hardly differ in handling and cooperation. It is more a question of trust, control and flexibility whether an advertiser moves their entire account to the MCC of the CSS partner or is connected via association.