Use case:
I am using software, I see the bug but I cannot fix it (I am a user). Also I cannot report it because it allready have been reported! And lies in bugzilla for 4 months or so without a further comments or activity.

The only optins are: I can stop using software, I can wait more, or vote for the bug to bring an attention to it.
To vote, currently I have to register and write a comment.

A feature:
I wonder if there is a such feature in bugzilla possible to introduce, to enable voting, without a need for placing a comment. It would give a chance to mark that this particular bug is important for someone, but in the way to not to bother developers by a single user.

If a bug will get some number of votes, it will be an indication that if it could be fixed sooner than those without any votes, it will make more people happier than in case of fixing in oposite order.
Also it could be a tool to remind about some forgotten bug, not fixed since months.

Such feature could be avialable without registering and logging on, to attract more users to bugzilla. Now its scary for ordinary user. A way to disallow robots from voting could be a simple image with code to rewrite.

Now developers have to read long comments instead of one number - number of votes. Also they have duplicate bug reports by impatient users.

An example of such forgotten bug is bug #552994
I vote for it.