Visiting.

http://cheddarbay.com/0000Tea/callingcards/callingcards.html

One would think that internet technology would have made escaping unwanted former acquaintances harder than previous eras.  Apparently not:

 According to the strict rules of etiquette, one call during the year, or a card left at the door in person or in an envelope, continues the acquaintance; although there is no apparent cause for this seeming remissness, society must ask no questions.  We can never know what prompts a lady to give up her visiting for a season, it may be a sudden calamity, or need of economy, or domestic duties, and she should not be questioned, for no doubt her reasons are purely personal.  

There should be uniformity in visiting. No lady is pleased to receive a card from Mrs. Allen and then meet her, making a personal visit (perhaps) to her next door neighbor. If a lady cannot personally visit all her formal acquaintances, she should visit none; for it is not proper to show favors, and the lady receiving the card would certainly feel the slight.