I am here to ask about every forum managers worst nightmare; a billion spam bots signing up on your forums daily due to useless capcha.
When I first used SMF, I recall it being a pre-2.0 version, and it either had no capcha or it wasn't working against bots. Now I am using the latest version, I ask, can I use the default capcha and be safe from spam (I noticed registering on this forum was very hard - took me 3 attempts, but its a whole other story for bots) or must I still install reCapcha?
Welcome to the site Callum_uk :)
While SMF 2.x comes with built in security measures like capcha and verification questions, this is not 100% affective. Using these built in functions along side a mod or two from the mod site (http://custom.simplemachines.org/mods/) will help manage spam or stop it altogether, I would recommend from personal use httpbl which through a combination of the built in SMF functions and post based groups has basically stopped all spam on the forums I managed.
The solution to my problem before was reCaptcha, http://custom.simplemachines.org/mods/index.php?mod=1044
Is this still an efficient mod? Worked perfectly before. Also, can you disable the default captcha?
I can't advise on reCaptcha mod as I've never had the need for it or used it. With regard to the standard captcha you can disable it by going to 'Administration Center » Security and Moderation » Anti-Spam' and change the 'Visual verification image to display' option to 'None'.