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.
http://money.cnn.com/2004/12/07/news/international/lenovo_ibm.reut/index.htm?cnn=yes Can't say I care as much as I might have when I owned an IBM, but I'm interested to see if it leads to some new products for the US market.