So long as the bots aren’t reading and understanding the CSS commands, you should be fine.

That would work too however I’ve never used any form bot software to tell how many of them it would catch up. Bots defiantly have issues with javascript, but I dont know about CSS. It would help if the CSS style specifying the display:none was in an external CSS sheet. Then they’d have to use/emulate a browser to find out that its hidden.

The input type would not be “hidden” but a regular text box. In order to trick the bot, you hide it with CSS or ASP, PHP or what-have-you. So it’s a normal text field, just hidden from human eyes.

I think it would be easy for a bot to detect a “hidden” string in the input tag. They want to act like users so I dont think that strategy would trip up most bots. Its all about bettering your odds though. Good idea.

I have another successful method that I’ve employed on a couple of site. This is not so much for pingback spammers, but is useful for your standard form spam-bots; those are the bots that run around the internet and submit garbage into your forms. I never quite understood why someone would do that… but anyway. My current blog doesn’t have this installed yet, but it’s my next order of business.

The effect is that you basically place hidden fields into your form that a bot will fill out. The hidden fields are named to trick the bot with names like “email” or “url.” When you process the form, if these hidden fields have a value, then you know the form was filled out by a bot, as a human would not have seen them, and would not have filled them out.

The method is pretty simple. Add an additional input field into your form. Give this the id and name of something like email, url or comment. Then take one of the fields that is normally part of the form, and rename it to something else, like “favorite_color.” The id of favorite_color is actually going to be their url, for example, so in the form processor, you will also need to change the id from url to favorite_color. Next you will need to hide the “url” form field with CSS. Lastly, you will need to create an exception check in the form processor to see if the hidden field has a value. If it does, then we know it’s spam, because a normal person wouldn’t see the field, and thus, would not fill it out, while a bot would see it and fill it out, thinking it’s the url field.

It sounds complicated, but once it’s completed, you won’t have to inconvenience your real readers with math questions or captcha boxes.

I’ve finally set Akismet to delete anything older than 30 days automatically, and I almost never check the spam section of my blogs anymore.

I’m sure I’m running a risk of missing a good comment, but the time savings has been worth it. Not to mention, I’ve quit burning my eyes with some of the filth that I used to have to skim through before deleting the spam comments and trackbacks manually.