Snape's birthday...will she or won't she?

[potioncat]

Snape's Witch 
> 
> Even more interesting is why she added Draco just before HBP was 
> published.


Potioncat:
Did she? I thought, but someone would need to confirm it, that over the 
course of one year, JKR wished Happy Birthday to selected characters. 
When the next year came around, the same set were there---no new names 
and no missing ones.

She's wished both Draco and Snape happy birthday after HBP came out. 
This was Snape's second greeting after HBP.