Google+ and Facebook do not share how their post spam filters and algorithms work. Using common sense, observation and testing  it is relatively easy to get an idea on what not to do

It is very tempting to post the same piece of great content you have just created to multiple facebook groups and Google+ communities. It is on topic and you are sure that people in those newsfeeds would find what you have to say interesting, enlightening and enjoyable. You want more people to see what you have discovered and are excited about sharing it with everyone. The problem is Google+ and Facebook view this as spamming. Your post will be deleted.

This happens because of the unscrupulous actions of bad marketers who upload the same promotional advertisement post to as many groups and communities as they can within a relatively short time period. They share and reshare the same content over and over again hoping to make a fast profit by getting their marketing information in front of as many eyes as possible. It is annoying so the software developers that work at facebook and Google+ came up with automated solutions that try to deal with this problem by finding and removing them. Their aggressive spam filters also capture your non commercial update if you post it to more than one location and share or reshare it. The solution is to write new individual content specifically aimed at each community or group

Facebook and Google also view posts that just contain a link to a blog or website article as poor quality. This also applies if you have only added one line of text. You run the risk of your post being flagged as spam. You should write a paragraph of information informing the reader why they should click your link and what they will find at the other end. It is also not a good use of your time just to put up a link as there is a poor click through rate. Readers want to know what will receive before they click a link. They are busy people and do not have time to waste.  Be aware that some communities and groups ban the use of small URL links like those obtained on web address shortening websites like bit.ly.

The problems really start once a few of your posts have been identified wrongly or correctly as spam. If you try to correct your error but use the same link then the spam filters may stop your new post being seen. They have a long memory. They record the link you used in their database. You may have to rename your website page if you want to link to this page in the future.. If you get an indication that your posts are being stopped or removed from the newsfeed than act immediately. Change the style of your post's content. Find out what you have been doing wrong and alter your style. If you continue sending out posts that get reported as spam or are continually caught by the spam filters there is a high risk of having your account closed. You will immediate loose all your fans and followers.