This is how you increase security on Yahoo Answers!
*Introduce captcha code
*Make the "sources" filed mandatory for all answers.
*Change your coding and algorithms to auto detect that the language input into a submission is correct for the version of Yahoo Answers being used.
*Alter your algorithms to detect and prevent content not in adherence to the question and answer format. If a response sounds too much like a question
*Introduce a character minimum of 250 characters for all answers. If it's less than 250 characters, it's probably not very informative anyway.
*Temporarily suspend any user who fails to submit a profile avatar and profile page bio within 24 hours of opening their account. If they are suspended for this reason, their suspension should only be lifted when they submit a profile picture. They should be given 7 days to submit a profile picture once suspended, failing to do so should result in the permanent deletion of their Yahoo Answers account. A selfie or bitmoji image should be more than acceptable. And all bios should be a minimum of 100 characters.
*New users should have to fill in a monitory survey to enhance their Yahoo Answers experience while serving as a means to combat spam at the same time. This should include asking the user to select a minimum of 5 different categories of interest, so you can tailer content of interest on the home page. They should also be asked what areas they hold expertise in, along with educational qualifications to these fields. Finally they should be asked why they want to join Yahoo Answers via multiple choice options.
This may not get rid of all of the current spam bots on your site, but it will help limit and filter it out in the future. I strongly suggest you implement my suggestions as soon as you can. Its in the interest of the community. Thank you for your time.
More....just remember, anything that would cost then users will really not be considered.
All good ideas, but several problems.
1. The bots could program the source to be "personal knowledge".
2. For the language idea, in that category two languages are allowed for translations.
3. For long answers, if the answer is NaCl or sodium chloride, more characters are not needed. Users would really object to this idea.
4. Complete profile would raise many objections from users.
5. Again, a survey would raise big objections. Users have shown time and again, fix the site but do not make users do anything more than doing now. Even a Captcha step would raise the roof.
I don't know about avatar and bio thing,some people would want to keep their anonymity.