I used to have left aligned websites, but the screen size at the time didn't matter, it fitted well. Then as screen size and resolution increased, it looked ugly.... (you can do wonders with backgrounds and liquid layouts).

Now, due to the new standards, remember that you are centered regarding your monitor, so avoid making your users look at the left or right side of the screen when the most natural position is facing forward, to the center of the screen...

just my opinion... but I never measured the diffs regarding that change, but if it serves you well, earnings have been climbing, only one site died but it was panda related, the rest continue to slowly climb

I design my layouts for users, not CTR.

What netmeg said, usability comes before monetizing. Also, with today's monitors, if you align a web site to the left (the only ones I've seen on the right were arabic or other languages writing from right to left), people are gonna have cramps in their necks. Go for center or a fluid design that takes up all the screen (or more ideally, all the width up to a maximum so it doesn't look silly on large monitors).

Go for center or a fluid design that takes up all the screen (or more ideally, all the width up to a maximum so it doesn't look silly on large monitors).

I align center at 928px (or 948 with wrapper) width (not fluid). This width fits the iPad landscape orientation perfectly, and it's just about right for most laptop, notebook, and even desktop users. Users with a high-res or very large screen see some white space to the left and right, but that's fine with me. The alternative is a fluid layout, which can make for pretty ugly experience for these users. (BTW, I don't bother (yet) with alternative style sheets for different devices.)

If you align center and limit the total pixel width you're assured that most users will at least notice an Adsense or other ad in a left or right column. That said, ads embedded in or immediately below content always yield the highest CTR. Agreed?

So no one has any experience so far then? The only thing I noticed regarding higher CTR and layout design is that 800x600 designs always have the highest CTR regardless of where you place the ads. Compact designs equals higher ctr.

I know the eyes look from left to right, so I'm wondering if having layout on the left will make a difference.

What netmeg said, usability comes before monetizing

I agree, but disagree as well. I'm on a dual monitor setup, and using 1920x1080 on both. If the browser window is fullscreen on one monitor, I only move my eyeballs. Never having to move my neck. I'm on a fairly large 24inch monitor also. Obviously I have to move if I'm on the other screen.

When I first starting building sites using Frontpage back in 19 dot dot, I always used to left align the pages (left hand navigation with content on the right). However, since monitors at that time weren't that big, it didn't really matter where the page was aligned to.

I then progressed to building sites using xsitepro always setting page widths to a maximum of 750px centered. Again, this was to accomodate the standard PC screen size of 800px. I stuck with 750px centered up until very recently when I started using a 950px width.

The extra 200 px of space allows for a wider left sidebar/navigation area while also allowing me to embed adsense units within the content without them standing out like a sore thumb. I have also increased page font size which gives mobile users a chance to actually read the content. I had tended to stick with 10pt font size but by the time that shrinks down to an ipod or ipad screen size, the text was becoming difficult to read resulting in high bounce rates by mobile users.

As regards the original layout on the left question, there are still plenty of sites that use that type of layout (think SBI), so they must be OK.

In any case, considering how close we sit to these oversized monitor screens, is it any wonder we have to move our head rather than our eyeballs to read what is on screen. How many times have we told our children not to sit too close to the TV screen and yet we do it all the time when on the computer.

My traffic is running around 50% mobile these days, so from here on in, all my sites will be Responsive Design.

Well for me, I'm trying to reach the magical 6 digits by the end of the year on one particular site. I guess I'll start testing to see what happens.

My earnings have been up every year, but I feel that this year, I can optmize my site, and my earnings even more.

My traffic is running around 50% mobile these days

I would be doing that as well however January I had 0.2% Blackberry, 0.1% Java Mobile but I did have 0.8% Android browser and 0.1% iPhone browser.

Does adsense actually show up on Blackberry, Android and iPhone?

I have read that these phones are not Javascript enabled although I can't prove it one way or the other since the mobile I do have is just that - a mobile phone without all the 'smart' bits.

AdSense definitely shows up on my iPhone. It showed up on one of my Blackberries but not the other one. I believe it shows up on Android, but I don't have one.

Currently I use a plugin that serves up mobile pages based on the user agent, and that uses Adsense for Mobile. I'll probably still use it for some user agents even after I get the Responsive Design frame built.

...from here on in, all my sites will be Responsive Design.

Count me in on the liquid layout/adaptive/responsive design side.
I'm hoping that it will help me regain some of my lost Google traffic.
Currently I have an 800 px wide layout from 12 years ago. I didn't want to mess with it because I was getting good results - until last spring when Google traffic started to erode.
A wider layout may provide a better content-to-ad ratio which is now a factor in Google search rankings.
See "Above The Fold" Algorithm Launch [webmasterworld.com...]
Though it is unclear what counts as content.