I have found that if you remove the "www." from mobile ads, you get better conversions. On the flip side, using the "www." on other ads get more CTR for me.
I am assuming you mean removing or adding it to the displayed links, right? It doesn't matter if the actual URL has or doesn't have that (since it's hidden from the view).
The note is the display URL. Not the landing page URL. so, rather then www.domain.com/sale use the mobile ad to display domain.com/sale Maybe it's due to it's a shorter display, but I have seen better click thur with removing the www on mobile ads across the board.
I have found removing the www. helps on both desktop and mobile ads. Also playing with display URLs is a really good way to increase quality score so test these also. Finally. On mobile ads test using m.site.com as a display URL ( even test using "buy on your mobile" on the ad copy ) - the mobile site tells users that the site is optimised for their experience and the mobile ad copy is relevant.
I don't know about that, thank you for the sharing this tips with us. I will try and get experience about that.
For the last 2 or 3 years (maybe more, I can't remember), Google automatically adds the www part of your display URL if you don't have it. They also convert it to lower case. So leaving it out should have no effect at all. Before the change in this policy however, it was a somewhat well-known fact that leaving the www portion out of the display URL resulted in higher click rates. Why? Beats me. Don't know and can't recall the effect on conversion rates. But since I discovered that, I still do not include www in my display URLs and capitalize the words in the URL as a matter of course and habit. Capitalized URLs also produced better results. I think the reason Google changes it is so that ads look more like the natural results. For display ads, the reverse was generally true: having www in the display URL had higher click rates. Again, why that would be I have no idea. Doesn't seem to make sense. So my data suggests just the reverse that you see. Would need to look more into it. Are you using the exact same ads, just one with and one without www? I also know that on display ads, whichever way you write the URL will be respected. Seems Google just passes along the ad without any changes. Maybe it's the same for mobile ads.
I"ve consistently seen adding the www. in display url converts better. Also, with recent testing, I see about 70% better results using m. on mobile ads. adding the www. in mobile was never better CTR.
Interesting. Something about the m. that triggers a response whereas a www. doesn't. Are you testing this with the same ads, just different display URLs? You need to do this and not assume that an ad did better just because of the display URL.