A facebook post can be your status update or the link that you shared or even a photo album. Unless you are super popular you must have noticed that some get the attention of many and some don't. There could be two reasons why you didn't get your friends' attention. The most straight forward reason would be that they were not interested in what you published and the other being they never saw it. The facebook wall is bit messy anyway. Sometimes you do miss the things of your interest even if they appear in the wall, unless you use filters and you are seriously organized. There could be another reason; which being your post never appeared in their walls.
A facebook post has a simple life cycle. The posts which appear in your facebook wall would be the most recent or the most popular; well, mostly a combination of it. The facebook shows you the things that you might be of interest. When listing a post in your wall the facebook considers the following,
1. How interactive you are with the owner of the post
2. How popular is the post
3. The date on which the post was published/shared
How interactive you are with the owner of the post
This is something I fancy and think that facebook is doing but I still can't prove this scientifically, so leaving that for later :)
How popular is the post
A post gains popularity from the feedback you get from your friends in your facebook. The likes and comments they make are the popularity generators. But facebook considers the date on which the post was initially published when calculating the popularity. Even if you have a very popular post which has lot of likes and comments but if the post was published sometime back, then facebook prefers to show fresh content (gossip) over that. The comments and likes you get are out of your control. But just imagine if your post gets a considerable amount of likes and comments daily that post's lifespan would increase. It will live longer than anticipated. But you can't do this unless you have your friends on your payroll and you are in control. But something you can really do is to moderate your responses. When you (the owner of the post) is required to enter in to the conversation make sure not to put all your input at once. Contribute gradually so your post will live long in your friends' walls.