Many many happy returns of the day to [[http://manish9ue.blogspot.com/|Manish]], and my dear mamu (maternal uncle, for the uninitiated) Shrikant (affectionately known as Babloo)
BTW, why do we wish everyone a //happy// birthday? I mean, is it just because it doesn’t make sense to wish someone a sad birthday, or are //we// really happy that its that person’s birthday or do we simply with that the person should be happy that its his/her birthday?
Like many other rhetorical phrases, such as “What’s up”, I treat this just as a string, not trying to decipher the meaning!
The original intention of the maker(s) could have been any one of what you have listed.
Pandey ji! aapne to ekdam hi chaap diya — meri nayi website/blog par aap pehle hain comment karne wale! :-) badhai ho, aapko bhi aur hamein bhi :-)