I think sometimes there is a need to post question as anonymous, reason being to avoid linking content of a question with the identity of the questioner. This may not be so evident or required on technical sites like stackoverflow.com but sometimes is a necessity on sites like http://fitness.stackexchange.com/ or maybe in future depression.stackexchange.com
On such sites user may not want to link his identity to some questions where he may detail about his being over-weight or skinny or maybe some other attribute which he may like to keep private and avoid making his concerns public, but still want to ask a question with valid data.
I am not suggesting that user asking question should not be registered or not responsible for content. I think all down-votes or up-votes should still be attributed to user, but this way most users would not suffer the new user restriction, and reputation could even be used for a bounty. The only change should be that while asking question a valid registered user can hide his identity (the whole user signature block/user card and the reputation should be replaced by "identity-hidden") and that question should not be listed in his public profile.
Anyway identity of questioner doesn't add much value to question. If we think such anonymous question may reduce social nature of Stack Exchange sites, and maybe majority of questions will become anonymous we can curb that by putting a daily or monthly limit per user or put a price of say 50 reputation per anonymous question.
PS: I don't think this is duplicate of
because motive for question and reason for feature request are different, and I propose a different solution too, because creating another account for asking such questions has many problems which having a single account doesn't have
- I don't have to manage other account
- If I keep single account I still may want to keep my details to be linked to my non-anonymous questions
- I may want to use reputations I earned as bounty for anonymous questions
Quora also allows anonymous questions and may be we can take some hint from there.