People are impatient, we all know that and so does Google. One of its 10 commandments is "Fast is better than slow" (Google tenthings)
If a web page is slow to load people will click off and follow another link. And because a search page is an extremely competitive place to be (All your competitors are listed there!), if you do not respect your visitor by loading your page instantly, you will lose them.
This has been extremely important in Paid Search (PPC) for a long time. After all, you pay your per click money to Google once someone clicks on Google, not when, and if, they land on your website.
Now Google has added a stick to the carrot by penalising further slow loading pages.
From June 18th, Google has implemented an additional landing page load time factor into its "keyword quality score", which will mean sites with slow loading pages or multiple redirects will end up paying more and/or not achieving as high an Ad position.
That means Google is trying to discourage "interstitial landing pages", lots of redirects, very heavy graphics, poorly written code, overburdened servers and the multitude of other reasons why pages are slow to load.
What does this mean to you? You need to carefully analyse all your landing pages, across a variety of factors, to ensure that not only do they meet exactly the point of why you have tried to attract a visitor to them, but that they load sufficiently quickly..
If you don't, you will lose quality score, which will mean that your minimum bids go up. This, in practise, means that you will either lose rank, need to bid more for your keywords or Google may not show your ads at all and, possibly, a combination of all of these across your account.
Which is all the more reason to make sure your landing pages are not only relevant, easily navigable, easy to understand and follow but quick to load!