There are tweet ads, yes. They are usually marked as "promoted"
I found it useful to "report as spam" the account they were coming from so at least you only see them once...
I found the new layout to be headache inducing for my english-speaking, left-to right-reading brain so I switched to the Chrome plug-in Silverbird on TVGugs recommendation... and haven't seen the promoted tweets since. Maybe that's because I'm using lists more... but it solved a lot of problems for me.
I'm in the process of downloading a Linux distro (linuxmint.com); it's taking forever...it's approximately 1.3GB in size and according to Firefox, it'll take about four hours to download. There are fourteen mirrors available for this download: