TOS stands for Terms of Service. They are binding rules that define what you can and can’t do on the site.
For example, Facebook has a TOS. Many groups and events have supplemental rules set by the organiser. This is also allowed.
If the TOS is broken, they can remove you from the network, and as with the spaces of others, respecting their rules is only right, and will ensure you can remain to interact.
You should always read the TOS and rules.
Kai Wilson-Viola writes under various names, and in all genres. Co-founder and webmistress of the IAG site, she writes content on request of members.
She has written several books including the Ten Hour Marketing Plan and 12×12 – tutorials for social media.
When not writing, she can be found maintaining sites, designing themes, managing a charity called the Less than Three foundation, gaming, knitting or reading.