Weird happenings with Cafe Press ad

[graceemae]

Whenever the cafepress ad shows up, I am unable to hit the back button (safari browser on a Mac).  When I look at the browser history, I see that the ad is inserting a webpage into my history and this prevents me from moving back to the previous e-hell page. 

The url that the ad is inserting into history is from "a.tellapart.com" - (I tried to paste it into this msg but it pasted about 20 lines of gibberish after the address).

This may be standard practice, but I've never seen it before, so I wanted to mention it.

Thanks.

[artk2002]

When that happens I either hit "back" twice in row, or I use the "back history" capability and select the page I want to be on.