http://www.cnn.com/2012/01/08/us/maine-missing-toddler/
"She said she didn't specify that she wasn't home that night in her initial CNN interview because she was trying to follow the directions of police, who have instructed her not to discuss details about the night Ayla disappeared."
I think in the Sunday video, she was being evasive in her answers. I could honestly tell that she wasn't there. The video seems to have 'expired' but when asked a question, she hesitated on her answers. When asked about (my words) 'regular family dinner'...she said she wouldn't comment on that. Since LE has NOT given us the list of people who were in the house, including Grandma if I'm not mistaken (it was our assumption) then I'm sure they didn't want that info out originally. Possibly once they saw/heard the video they informed her to go ahead...
I don't think any of it is sinister, although I do understand others believing it is. I think she answered the questions asked without giving away info LE did not want public as of yet.
I also don't think she was 'smirking' in her pictures - I believe the way her mouth is shaped and how her teeth are make it appear that way.