I know, most of you knew that Yahoo! develops its own services by copying the style of other existing services, just like what Matt Cutts revealed.

It can take a lot of work to come up with creative HTML. I remember when Google did a bunch of UI research to decide on a distinctive look for AdWords. We decided to go with pastel boxes with a darker border on the right-hand side of the search results: … Not too long afterwards, Yahoo! changed their side ads to pastel boxes with a darker border: … Then at some point, Google decided to go for a fresh look. After a ton of prototypes, testing, and internal research, we decided on a blue background for the top ads, with a blue line separating ads on the right-hand side: … Not too long afterwards, Yahoo! changed their top ads to a blue background, made the right-hand ads on a white background, and added a blue line separating the ads: …

And I know that you will never be surprised if Yahoo! copies again… this time the Digg’s style. Yodel Anecdotal revealed it:

We call it a Suggestion Board — you can browse suggestions from other site visitors or post your own. Digg-style voting means we can quickly discover what’s most important to users.

And you can see it by your self on most of the Yahoo!’s sites:

Check out the Suggestion Boards that are now live: Answers, Autos, Autos Custom, My Yahoo!, Pipes, Real Estate, Site Explorer, Travel, TV, Upcoming.org, Yahoo! Developer Network, and Yahoo! Developer Network Gallery. (You’ll also find links for these in the footer of each site’s homepage and a complete list is here.)

Maybe, it’s part of Yahoo!’s trademark…

• Sign up for PayPal and start accepting credit card payments instantly.
  As the world's number one online payment service, PayPal is the fastest way to open your doors to over 150 million member accounts worldwide.
• Promote your product to high quality, targeted websites and blogs.
  Find effective, influential blogs and highly targeted audiences to advertise.Choose to display your ad across entire blog networks to maximize your exposure to a wide audience.