[ColinCera]

Yes, but my point is that ads in the empty space around the central feed would not be "overwhelming" to anyone except chronic complainers.

Ad blocking is a problem for all ad-supported web sites. There are heavy-handed ways to thwart it, and I personally wouldn't mind if Twitter used such tactics — Twitter is a valuable service and I don't have any objection to them making money to keep the lights on and making a ton of profit on top.