Clients ask us frequently if they should do both PPC and SEO at the same time. Our answer is always the same - "it depends". Of course it depends mostly on whether the particular client can benefit from search engine marketing. If they can, then we talk. But if we don't believe it's the best use of their marketing budget, we work with them on other marketing campaigns. If search engine marketing can benefit the client, then the question is PPC, SEO or both. Often times both can get the best results.
SEO and PPC work well togehter in two ways: 1) brand strength and 2) branding vs. promotion.
Brand Strength: Studies have shown that when a company has 1st page placement in the Sponsored Links (PPC) and in the organic listings (SEO), it creates a synergistic approach. See the PackandRide.com example below. For example, PPC listings typically get about 24% of click-throughs on a SERP (search engine results page), while SEO gets the remaining 76%. That equals 100%. However, when 1st page placement is achieved for both SEO and PPC, the click-through rate exceeds 100% - that is, it is not 1+1=2, but rather 1+1=2+. The theory here is that brand strength and click-throughs are heightened when the searcher sees multiple listings for the same company.
Branding vs. Promotion: SEO is the best long-term branding strategy online, but what about promoting a certain product or service - or what happens when an important search phrase is so competitive that you can't get it onto page 1. That's where PPC can close the gap. Let's say you are in the moving business. You hear about a military post being relocated but the search phrase "military moves" isn't one of your targeted search phrases for SEO. So, you go after that term on the PPC side and position yourself to generate traffic from the recent announcement about moving the military base.
In summary, PPC and SEO both have their places in search engine marketing. Used at the right times in the right places, you can achieve significant, long term brand strength online as well as have the agility to responsd to current events and opportunities to promote your products and services.