Your attitude seems crazy to me, and totally OTT. No way is this chatty & friendly lady a stalker - what an insult to her.
She sounds to me like she is genuinely interested in other people - something which is becoming rare these days, more the pity, She is not even nosey in my book.
In my late Mum and Gran's day these are the dear ladies who would sit at their window smiling as they watched people go about their business, stand at their door or gate passing the time of day with others going by, or chat with others in the corner shop.
It is what is called neighbourly - again something which is sadly becoming a thing of the past.
As far as the Facebook connection goes - for many facebook has replaced that old-fashioned neighbourliness, and for most people that is a good thing. They want someone admiring their baby or toddler's picture, or their dog photos, or their new car, as people in a street would have done in the past.
Please, please consider what a massive slur your insinuation/allegation about this lady is - an insult that could damage this poor lady's reputation were you to be discussing her with others in your neighbourhood as you have done here.