DeeCee - 6:02 pm on Mar 22, 2012 (gmt 0) [edited by: DeeCee at 6:39 pm (utc) on Mar 22, 2012]
Well.. The thing about that is that there is really no reason to do so.
Blocking some other SEs, if they send no (relevant) visitors, such as for example Baidu, fake Baidu, Sogou and others can help you quite a bit, both with site performance and other. I have seen times, where if you have a large site, in some cases it can save your performance entirely for better use. One case, where that shaved 20-25% off overall site load.
But blocking an SE for the "sending no visitors" reason has little to no meaning, if they are not bothering your site otherwise. In that case you might as well just take what you can get.
[edited by: DeeCee at 6:39 pm (utc) on Mar 22, 2012]