There are some guys who seem to be flooding or spamming me. Is there a way to ignore or block a user, like what can be done in Facebook, for example?
No, you cannot ban a user. If you feel a user is trolling, flag one of their posts for moderator attention so they can look at it, and warn (or suspend) the user when necessary.
Only moderators can suspend users.
No users can be banned until moderators decide to permently destroy the account into shreds if that person seems to be too annoying in our digital society. Flag the user's post and in the
Other section, write your reason for wanting that user suspended if necessary. Also give a friendly warning. If the user ignores it, it might go against that user in the future... Other than that, just go on with life as we know it today.