I personally don't see the usefulness of it...or all that much of one anyway. I tried it out, and all you have to do is click on the link and open it up or even the option to undo the block completely.
If somebody quotes the blocked persons post in their post, it's going to show up anyway, and if something is mentioned about that blocked persons post, it's going to get our curiosity up as to what was said, and not only that, but the person being blocked doesn't even know it, they just don't have any of their posts ever quoted by you, and that happens anyway, whereas we just assume not everybody has something to add to what we're posting, unless we post thee ol' "I"M BLOCKING YOU" post, to let them know. Still...you're only pleasing yourself, in knowing this person is now BLOCKED from viewing.
Sorta like cutting an EX out of all your pictures. @lol@
Quite frankly, I think it's a little silly and prudish and only serves to satisfy some urge in us to stifle out people on our own, like my posted picture demonstrated with back turned, fingers in both ears and "la la la'ing" over top the noise, to block out stuff we don't won't to hear (or in this case...read). I guess if it gives us a sense of satisfaction in knowing we've BLOCKED out an objectionable members comments, as a power grab of sorts or a "HAH..take THAT..you're BLOCKED buddy!" then I guess it's got it's use?
I want to read what everybody has to say, good, bad and ugly. I want to see ALL the images everybody has to share, be it avatars, signatures or posted pictures of various sorts, to show a little something of their self and interests and what their made of. It's how I can judge people, and decide if I have something in commin with them, or relate to them somehow, other than just by the printed word alone. The features for all this are their for a reason, to be used as desired and add a little style to the board and a LOT of personality. :)
This block feature is another feature to be utilized if needed, but I doubt very seriously, I'd waste my time going through the motions and effort to do so. It's like when the wife is mad at me, and won't respond to me, ignoring me, even though she's right in the room and knows I'm there, she's pouting and ignoring me...or I guess "blocking" me? @lol@
If it helps those that feel they're easily angered by the stupidity of others or whatever it is that gets them fired up about them, then I guess it's a good thing.