John Resig has just put out a nice post about browser share.  It's well worth reading and I won't repeat what he says there.  I do, however, think the cost benefit balancing graph is a worth examining further.  If you take a look, it seems to say that IE7 is a lot of work, but worth targetting, whilst IE6 is not worth the effort.  However, this is very dependent upon the browser share and the traffic to your site.  The yellow bars, the cost, are pretty much constant across browsers.  The blue bars, the benefit, can be expressed as follows:...