I had a client request that they wanted a mailing list popup like the example given below where the popup is presented to the user as soon as they land on the site
I am a little concerned about the effectiveness of this popup in terms of conversion and the potential for it being an annoyance. I did some research on what the general view is on mailing list popups and there seems to be consensus that they can help in increasing conversions but they can be really annoying as well. However most of this information was garnered by discussions in forums about such methods to sign up people. I am wondering if there is any research on whether such a popup is bad usability or there are pros which outweigh the cons?