No, not all directories.. There are few trusted directories which can give you strong backlinks. Search engines scan their respective directories like Yahoo! directory and DMOZ for displaying results to the users.
pretty much. directory submissions don't do anything in terms of PR and almost anything in terms of traffic nowadays.
No it's not useless but the competitors that can make your endeavor is useless.you should try premium backlink on the high pr directories. analogy : it's the same thing with race competition.maybe it's hopeless if you cross the super champion.but it's more hopeless if you don't walk it
Back in the days of DMOZ and Yahoo Directory I think it was important to be on those directories, but nowadays visitors are finding web sites using alternative methods... (ask yourself; how many times have you used a 'directory' to find something in the last year??)
It depends on the keyword you are aiming for, and the age of your site and that of the directory, if the keyword is competitive then you may have your work cut out
You need to get BackLinks from High PR sites..at the same time Relevant Category sites to your Business
Directories are not useless. Actually what ever do for your link distribution will pay you off sometime. But the effects can take some time. In case of directories the links are listed deep inside. It makes your link crawling and indexing process a little slower. So you thinks that you are not being benifited. Just wait for while little. Hope things will work soon.